Pearson | PTE
Trusted by 3,500+ universities and colleges globally | Accepted for migration visa applications to AUS, CAN, New Zealand , and the UK
NCERT Exemplar Class 10 Science Solutions Chapter 8 How do Organisms Reproduce
Edited By Priyanka kumari | Updated on Sep 09, 2022 02:41 PM IST | #CBSE Class 10th
Ongoing Event
CBSE Class 10th Exam Date : 01 Jan' 2025 - 14 Feb' 2025
NCERT exemplar Class 10 Science solutions chapter 8 discusses the reproduction system of organisms such as plants and animals. The process of reproduction is an essential process for the life of any organism. Also, reproduction is a process for any organism’s existence because they create similar kinds of organisms by this process.
This Story also Contains
- NCERT Exemplar Class 10 Science Solutions Chapter 8-MCQ
- NCERT Exemplar Class 10 Science Solutions Chapter 8-Short Answer
- Question:28
- NCERT Exemplar Class 10 Science Solutions Chapter 8-Long Answer
- NCERT Class 10 Exemplar Solutions for Other Subjects:
- NCERT Class 10 Science Exemplar Solutions for Other Chapters:
- Features of NCERT Exemplar Class 10 Science Solutions Chapter 8 - How do Organisms Reproduce?
Our handpicked subject matter experts prepared these NCERT exemplar Class 10 Science chapter 8 solutions. They deliver complete solutions to questions given in NCERT Class 10 Science Book. These NCERT exemplar Class 10 Science chapter 8 solutions are adequate for the students to understand the concept. The CBSE 10 Syllabus chapter 8 is the source point in NCERT exemplar Class 10 Science solutions chapter 8.
NCERT Exemplar Class 10 Science Solutions Chapter 8-MCQ
Question:1
In the list of organisms given below, those that reproduce by the asexual method are
(i) banana
(ii) dog
(iii) yeast
(iv) Amoeba
(a) (ii) and (iv)
(b) (i), (iii) and (iv)
(c) (i) and (iv)
(d) (ii), (iii) and (iv)
Answer: B
Solution: Banana do not have seeds. They reproduce asexually by vegetative propogation. Yeast reproduce asexually by budding and amoeba by binary fission, multiple fission, sporulation and regeneration. Only dog reproduces by sexual method of reproduction.
Question:2
In a flower, the parts that produce male and female gametes (germ cells) are-
(a) stamen and anther
(b) filament and stigma
(c) anther and ovary
(d) stamen and style
Solution: Stamen is the male reproductive part of the flower and it consists of 2 parts-anther and filament. Anther is the top most part of the flower that produces male gametes-pollen grains. Carpel is the female reproductive part of the flower. It consists of stigma, style and ovary. Ovary is present at the base of the carpel and contains ovules- the female gametes.
Question:3
Which of the following is the correct sequence of events of sexual reproduction in a flower?
(a) pollination, fertilization , seedling, embryo
(b) seedling, embryo, fertilization , pollination
(c) pollination, fertilization , embryo, seedling
(d) embryo, seedling, pollination, fertilization
Solution: The correct sequence of events of sexual reproduction in flowers are:
Pollination, fertilization , embryo, seedling
(1) Pollination- the transfer of pollen grains to the stigma.
(2) Fertilization- the fusion of male gamete and female gamete produces zygote.
(3) Embryo – the zygote divides number of times by the process of mitosis and results in the formation of embryo.
(4) Seedling- the embryo differentiates and becomes plumule, radicle and one or two cotyledons.
Question:4
Offspring formed by asexual method of reproduction have greater similarity among themselves because
(i) asexual reproduction involves only one parent
(ii) asexual reproduction does not involve gametes
(iii) asexual reproduction occurs before sexual reproduction
(iv) asexual reproduction occurs after sexual reproduction
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)
Solution: In asexual reproduction, only single parent is involved and offsprings are directly produced from the parent by cell division, fragmentation, budding, etc. and it passes on the same genes from one generation to another. It doesnot involve any gametes. Thus offspring formed by asexual reproduction have similarities among themselves.
Question:5
Characters transmitted from parents to offspring are present in
(a) cytoplasm
(b) ribosome
(c) golgi bodies
(d) genes
Solution: Genes are the unit of heredity. They are present on chromosomes which are located in the nucleus of a cell. They carry genetic information from one generation to another and causes variation in the species.
Question:6
Characters that are transmitted from parents to offspring during reproduction show
(a) only similarities with parents
(b) only variations with parents
(c) both similarities and variations with parents
(d) neither similarities nor variations
Solution: The characters that pass on from parents to offspring show both similarity and differences. Similarity is because half of the chromosome comes from the father and another half comes from the mother. Variation is because of genetic recombination, mutation and natural selection.
Question:7
A feature of reproduction that is common to Amoeba, Spirogyra
and Yeast is that
(a) they reproduce asexually
(b) they are all unicellular
(c) they reproduce only sexually
(d) they are all multicellular
Solution: The common feature among amoeba, spirogyra and yeast is that they all reproduce by asexual method of reproduction. Amoeba reproduces by binary fission, spirogyra by fragmentation and yeast by budding.
Question:8
In Spirogyra, asexual reproduction takes place by
(a) breaking up of filaments into smaller bits
(b) division of a cell into two cells
(c) division of a cell into many cells
(d) formation of young cells from older cells
Solution: Spirogyra reproduces by both asexual and sexual method. They reproduce asexually by the process of fragmentation and sexually by conjugation. In fragmentation, spirogyra breaks into two or more segments and each segment results in the formation of new organism.
Question:9
The ability of a cell to divide into several cells during reproduction
in Plasmodium is called
(a) budding
(b) reduction division
(c) binary fission
(d) multiple fission
Answer: D
Solution: Plasmodium reproduces both asexually and sexually. Under unfavourable conditions, plasmodium forms a cyst around it and divides multiple times by the process of multiple fission and results in the formation of number of new cells.
Question:10
The correct sequence of reproductive stages seen in flowering plants is
(a) gametes, zygote, embryo, seedling
(b) zygote, gametes, embryo, seedling
(c) seedling, embryo, zygote, gametes
(d) gametes, embryo, zygote, seedling
Solution: The process of reproduction is divided into different stages. The first stage is the production of male and female gamete i.e., pollen and ovule respectively. The pollen grain reaches the stigma of flower by the process of pollination. The pollen germinates and forms pollen tube that reaches to the ovary and then male gamete is released. Male gamete fuses with female gamete and results in the formation of zygote.
The zygote divides several times to form an embryo. Then, there is seed development. Flowering plant's seeds have three parts, embryo formed from zygote, endosperm formed by double fertilization and seed coat formed by maternal tissue of ovule. The seeds under favorable conditions, germinate to produce a seedling.
Question:11
The number of chromosomes in parents and offsprings of a particular species remains constant due to
(a) doubling of chromosomes after zygote formation
(b) halving of chromosomes during gamete formation
(c) doubling of chromosomes after gamete formation
(d) halving of chromosomes after gamete formation
Solution: The gametes are produced by the process of meiosis where the number of chromosome in each gamete is halved. At the time of fertilization, the zygote thus formed has a full set of chromosomes. Therefore, the number of chromosomes in parents and offsprings of a species remain constant.
Question:12
In Rhizopus, tubular thread-like structures bearing sporangia at their tips are called
(a) filaments
(b) hyphae
(c) rhizoids
(d) roots
Solution: Rhizopus is a saprotrophic fungus which feeds on the dead and decaying matter of living organism. The body of rhizopus is made up of branching mycelia composed of three types of hyphae- rhizoids, stolons and unbranched sporangiophores. Hyphae are the filamentous structures that branch out and spread below the substratum surface like in case of bread.
Question:13
Vegetative propagation refers to formation of new plants from
(a) stem, roots and flowers
(b) stem, roots and leaves
(c) stem, flowers and fruits
(d) stem, leaves and flowers
Solution: Vegetative propagation is a type of asexual reproduction in which new plants are formed from the vegetative parts- stem, leaves, bud and root of the plants. The plants produced by vegetative propagation are genetically similar to the parent plant in all its characteristics.
Question:14
Factors responsible for the rapid spread of bread mould on slices of bread are
(i) large number of spores
(ii) availability of moisture and nutrients in bread
(iii) presence of tubular branched hyphae
(iv) formation of round shaped sporangia
(a) (i) and (iii)
(b) (ii) and iv)
(c) (i) and (ii)
(d) (iii) and (iv)
Solution: The factors responsible for rapid spread of bread mold on slices of bread are availability of moisture and nutrients in bread and formation of round shaped sporangia. The fungi spread rapidly through spores by sexual or asexual method. The spores germinate under favorable conditions and produces new hyphae.
Question:15
Length of pollen tube depends on the distance between
(a) pollen grain and upper surface of stigma
(b) pollen grain on upper surface of stigma and ovule
(c) pollen grain in anther and upper surface of stigma
(d) upper surface of stigma and lower part of style
Solution: The pollen tube helps in transporting pollen grains to the ovule inside which eggs are present. The pollen germinate on the upper surface of stigma. Hence, the length of pollen tube will depend on the distance between upper surface of stigma and lower part of ovule and it will ensure that pollen reaches the stigma and pollination is successful
Question:16
Which of the following statements are true for flowers?
(i) Flowers are always bisexual
(ii) They are the sexual reproductive organs
(iii) They are produced in all groups of plants
(iv) After fertilization they give rise to fruits
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (ii) and (iv)
Solution: The statement (ii) and (iv) are true while statements (i) and (iii) are false because flowers are not always bisexual. They can be unisexual also. Only angiosperms produce flowers while as bryophytes, pteridophytes and gymnosperms do not produce flowers.
Question:17
Which among the following statements are true for unisexual flowers?
(i) They possess both stamen and pistil
(ii) They possess either stamen or pistil
(iii) They exhibit cross pollination
(iv) Unisexual flowers possessing only stamens cannot produce fruits
(a) (i) and (iv)
(b) (ii), (iii) and (iv)
(c) (iii) and (iv)
(d) (i), (iii) and (iv)
Solution: In case of angiosperms, flowers can be unisexual or bisexual. The unisexual flowers have either stamen or pistil. Cross pollination is necessary in case of unisexual flowers. In both the types of flowers, pistil bears ovary. Fruit is ripened or matured ovary. After fertilization ovary undergoes major changes and its wall also thickens to produce a fruit. Flowers possessing only stamens cannot produce fruits because fruit is a mature ovary.
Question:18
Which among the following statements are true for sexual reproduction in flowering plants?
(i) It requires two types of gametes
(ii) Fertilization is a compulsory event
(iii) It always results in formation of zygote
(iv) Offspring formed are clones
(a) (i) and (iv)
(b) (i), (ii) and (iv)
(c) (i), (ii) and (iii)
(d) (i), (ii) and (iv)
Solution: Sexual reproduction is the process in which two parents i.e., male and female are involved. Male produces male gamete while female produces female gamete. During fertilization, the male and female gamete fuses to form the zygote. Reproduction is necessary for the continuation of the species. The offsprings resulting from asexual reproduction are exactly identical to the parents and are called as clones.
Question:19
In Figure 8.1, the parts A, B and C are sequentially
(a) cotyledon, plumule and radicle
(b) plumule, radicle and cotyledon
(c) plumule, cotyledon and radicle
(d) radicle, cotyledon and plumule
Solution: A represents the plumule that results in the formation of shoot. B represents the cotyledon where the food is stored. C represents the radicle which forms the roots. The embryonic axis comprises of a plumule and radicle, present on opposite sides of the point of attachment of cotyledons to the embryonic axis.
Question:20
Offspring formed as a result of sexual reproduction exhibit more variations because
(a) sexual reproduction is a lengthy process
(b) genetic material comes from two parents of the same species
(c) genetic material comes from two parents of different species
(d) genetic material comes from many parents
Solution: Sexual reproduction is the process in which two individuals of same species produces two different gametes i.e., one male gamete and another female gamete. These gametes upon fusion results in the formation of zygote which produces new offspring. Because of the contribution of two parents, offspring produce more variations.
Question:21
Reproduction is essential for living organisms in order to
(a) keep the individual organism alive
(b) fulfill their energy requirement
(c) maintain growth
(d) continue the species generation after generation
Solution: Reproduction is essential for the survival of the species because it helps in producing new generation of same species. All other life processes are essential to keep the organisms alive
Question:22
During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys
(a) loss of milk teeth
(b) increase in height
(c) cracking of voice
(d) weight gain
Solution: Following changes occur in the body of the boys during adolescence-
Question:23
In human females, an event that reflects onset of reproductive phase is
(a) growth of body
(b) changes in hair pattern
(c) change in voice
(d) menstruation
In females, menstruation marks an event that reflects the onset of reproductive phase. This phase is marked by the discharge of the endometrial lining and the unfertilized egg through the vagina. This process continues for about 5-7 days.
Question:24
In human males, the testes lie in the scrotum, because it helps in the
(a) process of mating
(b) formation of sperm
(c) easy transfer of gametes
(d) all the above
Testes is present in a muscular bag called as scrotum which lies outside the body cavity. Testes help in the formation of sperms because the sperm production requires lower temperature than the body.
Question:25
Which among the following is not the function of testes at puberty?
(i) formation of germ cells
(ii) secretion of testosterone
(iii) development of placenta
(iv) secretion of estrogen
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Gonads helps in the production of hormones and gametes. In case of males, testes produce sperms and testosterone. Placenta is formed in females during pregnancy. It has a number of functions, like the production of hormones, nutrition, excretion etc. Estrogen is a female hormone produced by the ovaries.
Question:26
The correct sequence of organs in the male reproductive system for transport of sperms is
(a) testis vasdeferens
urethra
(b) testis ureter
urethra
(c) testis urethra
ureter
(d) testis vasdeferens
ureter
Solution: Testes produce sperms which are stored in the epididymis and are transported to the urethra through vas deferens.
The correct sequence is- testis
Question:27
Which among the following diseases is not sexually transmitted?
(a) Syphillis
(b) Hepatitis
(c) HIV - AIDS
(d) Gonorrhoea
Solution: Syphillis and Gonorrhoea are sexually transmitted diseases. Syphilis is caused by Teponema pallidum and gonorrhoea is caused by Neisseria gonorrhoeae.
AIDS is a sexually transmitted viral disease caused by HIV.
Hepatitis is caused through contaminated water and food. In hepatitis, the inflammation of the liver is caused by the virus which spreads through body fluids, blood etc of the person suffering from the disease.
NCERT Exemplar Class 10 Science Solutions Chapter 8-Short Answer
Question:28
Answer:Even though the young stamens (produce pollen grains) are being removed, carpel (producing eggs) exhibits cross pollination either with the flower of same plant or different plant of same species termed Geitonogamy and Xenogamy respectively.
Papaya is dioecious plant, which has either male or female flowers on a tree. Yet female tree produces fruits by cross pollination. Male tree doesn’t bear any fruits.
By removing stamens of a flower, only autogamy is prevented but not Geitonogamy or Xenogamy.
Question:29
Can you consider cell division as a type of reproduction in unicellular organism? Give one reason.
Answer:
Unicellular organisms reproduce asexually by cell division of parent cell. Parent cell divides into two daughter cells. Here parent cell does not tend to get old and die therefore unicellular organisms are even considered as biologically immortal.Hence, cell division can be considered as a mode of reproduction in single celled organisms, eg., Amoeba.
Question:30
What is a clone? Why do offsprings formed by asexual reproduction exhibit remarkable similarity?
Answer:
Clone refers to either group of cells or organisms which are produced asexually from a cell or individual organism. Clones exhibit remarkablesimilarity because they possess exact copies of the DNA of their parent.
Clones are produced by asexual means from the single parent so these cells tend to have similar genetic material as a parent because asexual reproduction
shows no gamete formation by meiosis or fertilization of male and female gametes.
Hence offspring's of asexual reproduction are similar among themselves and with parent organism as there is no genetic recombination.
Question:31
Answer:
Meiosis is also known as the reductional division is responsible for the formation of gametes. Meiosis reduces the number of chromosomes to half in male and female gametes.For example, an organism with the diploid condition (2n) has 20 chromosomes, then its gametes are haploid (n) with 10 chromosomes.
After fertilization of the male (n) and female gametes (n), the zygote formed will be diploid (2n). Hence, fertilization restores the normal chromosome number of organisms.
Question:32
Answer:
Colonies of yeast fail to multiply in water but multiply in sugar solution.Water does not have all the required nutrients necessary for growth and reproduction of yeast cell whereas sugar solution serves as an organic source for cellular respiration which releases energy for necessary cellular activities such as reproduction. That is why yeast fail to multiply in water.
Question:33
Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?
Answer:
Moist condition is suitable for the germination of spores and growth of hyphae. Even though bread is a suitable source of nutrients but dry condition wouldn’t allow spores to germinate.That is why bread mould grow profusely on a moist slice of bread rather than on a dry slice.
Question:34
Give two reasons for the appearance of variations among the progeny formed by sexual reproduction.
Answer:
Meiosis and fertilization are the two reasons for the appearance of variations in sexual reproduction. There is an event in meiosis termed as crossing over which leads to genetic recombination and variation. In fertilization, a random fusion of two gametes of different genetic lines is responsible for the variation.Question:35
Answer:
Yes a Planaria cut vertically into two halves regenerate into two individuals because planaria exhibits regeneration. Shaded part in Figures D and E represent the regenerated halves.
Question:36
From the internet, gather information about the chromosome numbers of five animals and five plants. Correlate the number with the size of organism and answer the following questions.
(a) Do larger organisms have more number of chromosomes/cells?
(b) Can organism with fewer chromosomes reproduce more easily than organisms with more number of chromosomes?
(c) More the number of chromosomes/cells greater is the DNA content. Justify.
Answer:
Rice 24 Housefly 8
Apple 34 Dog 78
Potato 48 Butterfly 380
Onion 16 Human 46
Maize 20 Rat 42
(a) No, there is a relation between the size of the organism and the number of chromosomes.
(b) No, the reproduction process depends on environmental factors such as availability of water, pollinator etc. and not on the number of chromosomes
in organisms.
(c) Yes, genes are segments of DNA. DNA is closely packed into chromosomes hence more chromosome means greater the DNA.
Question:37
Answer:
We know that Gametes have a haploid number of chromosomes that are present for both the gametes. Given that male gamete has 24 chromosomes, so the female gamete also has 24 gametes. By fusion of gametes to form a zygote, the zygote reestablishes 48 number of chromosomes.Hence,
Number of chromosomes in a female gamete of tobacco plant-24
Number chromosomes in zygote-48
Question:38
Why cannot fertilization take place in flowers if pollination does not occur?
Answer:
Fertilization cannot take place in flowers if pollination does not occur because without pollination male and female gametes cannot come closer. Pollination is the process by which the pollen is transferred from the anther or male part to the stigma or the female part of the plant. Fertilization requires male and female gametes. Hence pollination of any kind (autogamy, geitonogamy, xenogamy) is required to get male and female gametes closer.Question:39
Answer:
Yes, the chromosome number of the zygote, embryonal cells and adult of a particular organism is always constant. Sexual reproduction includes gamete formation through meiosis and fertilization. Meiosis reduces the number of chromosomes to half in male and female gametes. This reduced chromosome number is then restored to normal during fertilization of male and female gametes. A zygote is formed by the fusion of gametes.Once formed, it undergoes mitotic divisions. Embryonal cells also divide by mitosis to produce more of its kind. The cells in the adult organism also divide by mitosis. Hence mitosis in gamete formation and fertilization together maintain the chromosome number in the zygote. Embryo and adult form is formed from zygote by mitosis division (equational division).
Question:40
Where is the zygote located in the flower after fertilization?
Answer:
Zygote is located inside the female gametophyte (embryo sac) which is located inside ovule. After fertilization, ovule transforms into seeds and ovary into fruit.Question:41
Reproduction is linked to stability of population of a species. Justify the statement.
Answer:
Reproduction is the process of production of organisms of its own kind and maintaining continuity generations after generations. Reproduction produces offspring's which are with some similarities and variations with parents' due to genetic recombination and fertilization.This ensures them to overcome struggles such as competition for natural resources, habitation, predation etc. This is how reproduction ensures the stability of species and genetic heredity of characters.
Question:42
How are general growth and sexual maturation different from each other?
Answer:
General growth is associated with increase in number of cells, size, weight, height, of an organism. General growth is also referred to as somatic phase of growth which is similar in either of sexes and reproductive organs are less active.Sexual growth includes all the changes body undergoes for sexual reproduction. It ensures onset of puberty and reproductive phase in an individual. Sexual growth is different in both sexes with noticeable changes such as beard and mustache in males, and high-pitched voice and onset of menstruation in females.
Question:43
Answer:
Testis - Epididymis - Vas deference - UrethraTestis secrets androgens (testosterone).
Prostate gland secrets thin milky alkaline fluid that adjusts the pH of seminal fluid and serves in the motility of sperms. Bulbourethral glands/Cowper gland secretions are meant for the lubrication of penis during sexual intercourse. Seminal vesicles add fructose (nutrient), calcium (mineral element), and alkaline pH to counteract the acidic pH of the vagina
Question:44
What changes are observed in the uterus if fertilization does not occur?
Answer:
In the absence of pregnancy, there is abrupt fall in the progesterone levels which disintegrates the thickened endometrium and sloughs off during menstruation phase (1-5 days). There will be a drop in the hormone levels, which will cause the uterus to shed its lining and egg in the process called menstruation, where there is blood and uterine secretions are removed through the vagina.Question:45
What changes are observed in the uterus subsequent to implantation of young embryo?
Answer:
Ruptured graafian follicle transforms into corpus luteum which secrets progesterone which is necessary for thickening of endometrium. Disc like structure is formed by interdigitation of maternal tissue and embryonal tissue which is referred as placenta.Placenta serves to provide nutrients and oxygen from mother's blood to embryo and also removes waste generated by embryo. The embryo and placenta are connected by umbilical cord.
Question:46
What are the benefits of using mechanical barriers during sexual act?
Answer:
Benefits of using mechanical barriers during the sexual act are:(i) It serves as a barrier to prevent unwanted pregnancies and act as a gap between the offspring.
(ii) It also protects from sexually transmittable diseases (STD’s).
Question:47
In the given Figure 8.3 label the parts and mention their functions
(a) Production of egg
(b) Site of fertilization
(c) Site of implantation
(d) Entry of the sperms
Answer:
(a) OVARY - production of egg.
(b) OVIDUCT - site of fertilization .
(c) UTERUS - site of implantation.
(d) VAGINA - passage for entry of sperms.
Question:48
Answer:
The ratio of number of chromosomes in egg and zygote is 1:2. The egg is formed by reductional division from the parent cell. Zygote (2n) is formed by fertilization of male (n) and female (n) gametes. Sperms are different from eggs by chromosome number 23 as sperm can either be X or Y chromosome whereas egg has an only X chromosome.NCERT Exemplar Class 10 Science Solutions Chapter 8-Long Answer
Question:49
Answer:
Asexual reproduction is uniparental and it does not involve gamete formation and fertilization. As fragmentation, budding and regeneration none of these involves gamete formation & fertilization, and all of them produce individuals from single parents only hence these are considered as asexual reproduction.Regeneration is asexual reproduction in which organism has the ability to regenerate the lost (or) damaged body parts, for example, if a planarium is cut into small pieces then each piece develops into a new individual.
Question:50
Answer:
Variations are seen in sexual reproduction because of the fusion of genetically different gametes- fertilization. Gametes are formed by meiosis where there is an event termed crossing over which leads for genetic recombination. Even independent assortment of gametes is also responsible for variations in sexual reproduction.
Question:52
Distinguish between a gamete and zygote. Explain their roles in sexual reproduction.
Answer:
ROLE OF GAMETES AND ZYGOTE IN SEXUAL REPRODUCTION:
Gametes are the product of meiosis and hence carry half the chromosome number as that of parent cells. This chromosome number is restored during fertilization and zygote formation. Hence, gamete and zygote are the two phases of sexually reproducing organisms that help maintain the constant chromosome number in each species.
Question:54
What is placenta? Mention its role during pregnancy?
Answer:
The placenta is formed by outer layer trophoblast of embryo and endometrium. It starts to form after implantation of blastocyst around 12 weeks of pregnancy. It is a disc-like structure formed by interdigitation of maternal tissue and chorionic villi of embryonal tissue forming a structural unit referred to as placenta.Placenta serves to provide nutrients and oxygen from the mother's blood to embryo and also removes waste generated by the embryo. The fetus and placenta are connected by the umbilical cord.
Question:
What are various ways to avoid pregnancy? Elaborate any one method.
Answer:
Various ways to avoid pregnancy:Natural methods
(a) Periodic abstinence - abstain from sexual intercourse during the fertile period (10-17 day of the menstrual cycle)
(b) Lactational amenorrhea - ovulation generally will not occur during the period of intense lactation.
Barrier methods
(a) Condoms - made of thin rubber latex sheath, prevents ejaculated sperms from reaching the uterus.
(b) Other barrier methods are diaphragms, cervical caps, and vaults
Intrauterine devices – These are devices inserted into the uterus by doctors or trained nurses through the vagina. These are of different types such as non-medicated (lippes loop), copper releasing (Cu T, multi-load 375), hormone-releasing (Progestasert, LNG-20).
Oral contraceptive pills – Oral administration of small doses of progesterone – estrogen combination in the form of pills, eg. Saheli.
Surgical methods - Vasectomy (vas deference are cut and tied ensuring the absence of sperms in semen), tubectomy (fallopian tubes are cut and tied preventing ovum reaching uterus).
Question:56
How does fertilization take place? Fertilization occurs once in a month. Comment.
Answer:
The sperms released during sexual intercourse enter through the vagina and travel upwards and reach the oviducts which is the site of fertilization, where they fuse with the egg forming zygote which gets implanted in the uterus. Millions of sperms are released during ejaculation at the sexual intercourse, but only one sperm gets to fuse with the ovum. Ovulation release of ovum from ovary occurs only once in a month on 14th day of the menstrual cycle. Hence fertilization can occur only once in a month.Question:57
Answer:
Reproduction is the process of production of organisms of its own kind and maintaining continuity generations after generations. Reproduction produces offspring's which are with some similarities and variations with parents due to genetic recombination occurred during gamete formation by crossing over and independent assortment and fertilization of male and female gametes. Such variation ensures them to overcome struggles such as competition for natural resources, habitation, predation etc.Therefore, reproduction not only restores the number of individuals removed from the species by above mentioned natural forces but also maintain heredity of genetic characters and introduction of variations, as needed for continuity and stability of a species.
Question:58
Describe sexually transmitted diseases and mention the ways to prevent them.
Answer:
Sexually transmitted diseases/venereal diseases/ reproductive tract infections. STDs are infectious diseases transmitted by sexual intercourse and bodily fluids such as semen, blood etc. Few STDs and their causative organismsDISEASE CAUSATIVE ORGANISM
AIDS (acquired immune deficiency syndrome) HIV (human immunodeficiency virus)
GONORRHOEA Neisseria gonorrhoea
SYPHILIS Treponema pallidum
GENITAL HERPES Herpes simplex virus
Preventive measures:
(I) avoid sex with multiple partners
(ii) avoid unprotected sexual activities and maintain personal hygiene.
(iii) stop sharing needles, as there are chances for the transition of bodily fluids.
The Fundamental Topics Covered in NCERT Exemplar Class 10 Science Solutions Chapter 8 Are Mentioned Underneath:
- Different methods and processes of reproduction.
- NCERT exemplar Class 10 Science solutions chapter 8 discusses the reproduction process of plants and animals.
- Similarity as well as the dissimilarity between the production process of plants and animals.
- Organs which are responsible for reproduction in any organism.
NCERT Class 10 Exemplar Solutions for Other Subjects:
- NCERT Exemplar Class 10 Maths solutions
- NCERT Exemplar Class 10 Science solutions
NCERT Class 10 Science Exemplar Solutions for Other Chapters:
Chapter |
Features of NCERT Exemplar Class 10 Science Solutions Chapter 8 - How do Organisms Reproduce?
- These Class 10 Science NCERT exemplar chapter 8 solutions discuss the process of reproduction in plants and animals.
- The students can understand the questions based on How Organisms Reproduce elaborately by going through the NCERT exemplar solutions chapter 8.
- The Class 10 Science NCERT exemplar solutions chapter 8 How do Organisms Reproduce are sufficient to practice and score well while attempting problems from books such as S Chand Lakhmir Singh Biology Class 10, Biology question bank, and NCERT Class 10 Science.
- The feature of NCERT exemplar Class 10 Science solutions chapter 8 pdf download provides students with the convenience to explore the solutions offline while studying.
Check NCERT Solutions for questions given in the book
| Chapter No. | Chapter Name |
| Chapter 1 | Chemical Reactions and Equations |
| Chapter 2 | Acids, Bases, and Salts |
| Chapter 3 | Metals and Non-metals |
| Chapter 4 | Carbon and its Compounds |
| Chapter 5 | Periodic Classification of Elements |
| Chapter 6 | Life Processes |
| Chapter 7 | Control and Coordination |
| Chapter 8 | How do Organisms Reproduce? |
| Chapter 9 | Heredity and Evolution |
| Chapter 10 | Light Reflection and Refraction |
| Chapter 11 | The Human Eye and The Colorful World |
| Chapter 12 | Electricity |
| Chapter 13 | Magnetic Effects of Electric Current |
| Chapter 14 | Sources of Energy |
| Chapter 15 | Our Environment |
| Chapter 16 | Sustainable Management of Natural Resources |
Must check NCERT Solution Subject Wise
Read more NCERT Notes Subject Wise
Also Check NCERT Books and NCERT Syllabus here
Frequently Asked Questions (FAQs)
1. Q1. What is asexual reproduction?
A1. In this type of reproduction, there is no fusion of gamete. There will be no change in chromosomes, and the newborn will have the same gene as a single parent.
2. Q2. Why do we reproduce?
A2. Reproduction is not an essential process for the life of any being. It is vital for the existence of life for long. Every organism has an instinct for reproduction. It can be seen as a concept of natural selection.
3. Q3. What is binary fission reproduction?
A3. It is a process of reproduction, and the unicellular organisms generally show it. The unicellular organism gets divided itself into two parts, and both parts start living separately as newborns.
4. Q4. What is the percentage share of How do Organisms Reproduce chapter in board examination?
A4. The chapter has the highest weightage in the board examination and amounts to about 12-13% of the paper’s total marks. NCERT exemplar Class 10 Science solutions chapter 8 are precisely designed to acquire high scores in this chapter.
Also Read
Articles
Certifications By Top Providers
My SQL Basics
Via Great Learning Full-Stack Web Development
Via Masai School Digital Banking Business Model
Via State Bank of India Business Analytics Foundations
Via PW Skills Full-Stack Android Development
Via Masai School Banking 101 A Guide for Beginners in the Banking Sector
Via EduBridge Edx
1115 coursesCoursera
816 coursesUdemy
394 coursesFuturelearn
295 coursesHarvard University, Cambridge
98 coursesUniversity of Michigan, Ann Arbor
83 coursesExplore Top Universities Across Globe
University of Essex, Colchester
Wivenhoe Park Colchester CO4 3SQUniversity College London, London
Gower Street, London, WC1E 6BTThe University of Edinburgh, Edinburgh
Old College, South Bridge, Edinburgh, Post Code EH8 9YLUniversity of Bristol, Bristol
Beacon House, Queens Road, Bristol, BS8 1QUUniversity of Delaware, Newark
Newark, DE 19716University of Nottingham, Nottingham
University Park, Nottingham NG7 2RDLOR Full Form in Education - Letter of Recommendation
5 min ⋆ Oct 24, 2024 11:10 AM ISTTop 10 Easiest Countries To Go To Study Abroad In 2025
7 min ⋆ Dec 31, 2024 10:12 AM ISTMagister Jurisdiction
4 min ⋆ Mar 18, 2023 16:03 PM ISTCheapest and Affordable Universities in Ireland in 2025
15 min ⋆ Dec 31, 2024 03:12 AM ISTGMAT Exam Dates 2025: City Wise Test Schedule in India
13 min ⋆ Dec 31, 2024 03:12 AM ISTLetter of Recommendation: How to Write LOR, Samples and Format
9 min ⋆ Dec 31, 2024 03:12 AM ISTQuestions related to CBSE Class 10th
Have a question related to CBSE Class 10th ?
Hello Aspirant, Hope your doing great, your question was incomplete and regarding what exam your asking.
SWETCHCHA MISKA 10 July,2024
Yes, scoring above 80% in ICSE Class 10 exams typically meets the requirements to get into the Commerce stream in Class 11th under the CBSE board . Admission criteria can vary between schools, so it is advisable to check the specific requirements of the intended CBSE school. Generally, a good academic record with a score above 80% in ICSE 10th result is considered strong for such transitions.
Manasvini Gupta 23 July,2024
hello Zaid,
Yes, you can apply for 12th grade as a private candidate .You will need to follow the registration process and fulfill the eligibility criteria set by CBSE for private candidates.If you haven't given the 11th grade exam ,you would be able to appear for the 12th exam directly without having passed 11th grade. you will need to give certain tests in the school you are getting addmission to prove your eligibilty.
best of luck!
Ashvadha 03 July,2024
According to cbse norms candidates who have completed class 10th, class 11th, have a gap year or have failed class 12th can appear for admission in 12th class.for admission in cbse board you need to clear your 11th class first and you must have studied from CBSE board or any other recognized and equivalent board/school.
You are not eligible for cbse board but you can still do 12th from nios which allow candidates to take admission in 12th class as a private student without completing 11th.
sadafreen356 03 July,2024
Yes, you can definitely apply for diploma courses after passing 10th CBSE. In fact, there are many diploma programs designed specifically for students who have completed their 10th grade.
Generally, passing 10th CBSE with a minimum percentage (often 50%) is the basic eligibility for diploma courses. Some institutes might have specific subject requirements depending on the diploma specialization.
There is a wide range of diploma courses available in various fields like engineering (e.g., mechanical, civil, computer science), computer applications, animation, fashion design, hospitality management, and many more.
You can pursue diplomas at various institutions like:
- Polytechnics
- Industrial Training Institutes (ITIs)
- Community Colleges
-
Private Institutes (after checking their affiliation and accreditation)
https://school.careers360.com/exams/cbse-class-10th
I hope it helps!
Nitin Kumar 14 June,2024
Popular CBSE Class 10th Questions
A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is
| Option 1)
|
Option 2)
|
| Option 3)
|
Option 4)
|
An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range
| Option 1)
|
Option 2)
|
| Option 3)
|
Option 4)
|
A particle is projected at 600 to the horizontal with a kinetic energy . The kinetic energy at the highest point
| Option 1)
|
Option 2)
|
| Option 3)
|
Option 4)
|
In the reaction,
| Option 1)
|
Option 2)
|
| Option 3)
|
Option 4)
|
How many moles of magnesium phosphate, will contain 0.25 mole of oxygen atoms?
| Option 1)
0.02 |
Option 2)
3.125 × 10-2 |
| Option 3)
1.25 × 10-2 |
Option 4)
2.5 × 10-2 |
Colleges After 12th
Applications for Admissions are open.
JEE Main Important Physics formulas
ApplyAs per latest 2024 syllabus. Physics formulas, equations, & laws of class 11 & 12th chapters
JEE Main Important Chemistry formulas
ApplyAs per latest 2024 syllabus. Chemistry formulas, equations, & laws of class 11 & 12th chapters
TOEFL ® Registrations 2024
ApplyAccepted by more than 11,000 universities in over 150 countries worldwide
Pearson | PTE
ApplyTrusted by 3,500+ universities and colleges globally | Accepted for migration visa applications to AUS, CAN, New Zealand , and the UK
JEE Main high scoring chapters and topics
ApplyAs per latest 2024 syllabus. Study 40% syllabus and score upto 100% marks in JEE
JEE Main Important Mathematics Formulas
ApplyAs per latest 2024 syllabus. Maths formulas, equations, & theorems of class 11 & 12th chapters
News and Notifications
Board Exam Date 2025 Live: Bihar Class 10, 12 model papers out, time table soon; updates on CBSE, UP
December 06, 2024 - 10:42 PM IST
November 20, 2024 - 10:02 PM IST
November 14, 2024 - 03:21 PM IST
November 13, 2024 - 07:53 AM IST
October 24, 2024 - 09:54 PM IST
October 11, 2024 - 08:56 AM IST
September 05, 2024 - 07:38 PM IST
Stay up-to date with CBSE Class 10th News
Back to top