NCERT Exemplar Class 9 Science Solutions Chapter 6 Tissues

Question:1

Which of the following tissues has dead cells?
(a) Parenchyma
(b) Sclerenchyma
(c) Collenchyma
(d) Epithelial tissue
Answer- (b)
Parenchyma- These cells are located in the soft parts of the plants. They are living in nature and have a thin cell wall, dense cytoplasm and central vacuole.
Sclerenchyma- It consists of dead tissues with thick cell wall because of the presence of lignin. They are located in the veins of the leaf, covering of the seeds and vascular bundles.
Collenchyma- It consists of living tissues with an elongated shape and thick cell wall. It can be located in the stalk of the leaf and below the epidermis.
Epithelial tissues- These are protective tissues found in the animal body. They cover all organs and cavities in the animals.

The correct option is (b)- Sclerenchyma

Question:2

Find out incorrect sentence
(a) Parenchymatous tissues have intercellular spaces
(b) Collenchymatous tissues are irregularly thickened at corners
(c) Apical and intercalary meristems are permanent tissues
(d) Meristematic tissues, in its early stage, lack vacuoles
Answer- (a)
Solution- The Statement (a) is incorrect. Parenchymatous tissue is a permanent tissue and does not divide after differentiation. They donot have intercellular spaces. Parenchyma act as a packing tissue in plants. Collenchymatous
Tissues have intercellular spaces.

The correct option is- (a)- Parenchymatous tissues have intercellular spaces

Question:3

Girth of stem increases due to
(a) apical meristem
(b) lateral meristem
(c) intercalary meristem
(d) vertical meristem
Answer- (b)
Solution- The increase in the girth of a stem is due to the presence of lateral meristematic tissues. They are found in the cork cambium and in the vascular bundles of dicot roots and stems called vascular cambium as thin layers. This increase in the diameter and girth of the plant is called secondary growth.
Apical meristems can be found in the growing parts of a plant like shoot or root tips etc.
The intercalary meristems are located in the internodes at the base of the grass and between leaves.
The correct option is- (b)- lateral meristem

Question:4

Which cell does not have perforated cell wall?
(a) Tracheids
(b) Companion cells
(c) Sieve tubes
(d) Vessels
Answer- (a)

Solution- Tracheids and vessels are present in the xylem and help in water conduction.
These are tube-like structures with partially or completely dissolved walls to form water pipes (in vessels) and pits in the cell wall (in tracheids) for water conduction. Companion cells possess a perforated cell wall. Sieve tubes consist of sieve elements which are elongated cells, connected to each other via sieve plates to form a continuous tube system that spreads out through the entire plant.
They are present in the phloem and are the main food-conducting elements.
The correct option is- (a)- Tracheids

Question:5

Intestine absorb the digested food materials. What type of epithelial cells are responsible for that?
(a) Stratified squamous epithelium|
(b) Columnar epithelium
(c) Spindle fibres
(d) Cuboidal epithelium
Answer is (b) Columnar epithelium
Solution-Stratified squamous epithelium cells are present in the outer layer of skin, inner lining of the mouth, oesophagus, and vagina. Columnar epithelium consists of a single layer of columnar cells, which are attached to the basement membrane.
These are present in the digestive tract in the stomach, large intestine, small intestine and functions as a barrier to bacteria and other microbes but permits the absorption of digested food. Spindle fibres are structures made up of proteins which arise from centrioles in a cell during a process of cell division i.e., mitosis. Cuboidal epithelium is a monolayer of epithelial cells located in kidney tubules, glandular ducts, ovaries, etc. and they function in protection, secretion and absorption.
The correct option is (b)- Columnar epithelium

Question:6

A person met with an accident in which two long bones of hand were dislocated. Which among the following may be the possible reason?
(a) Tendon break
(b) Break of skeletal muscle
(c) Ligament break
(d) Areolar tissue break
Answer- (c)
Solution: The person must have broken the ligament that causes dislocation of bones and leads to the fracture.
The breaking of tendons causes inflammation because tendons help in joining the skeletal muscles.
The breaking of skeletal muscle cannot cause bone dislocation as ligaments join bones.
Areolar tissues are found in the muscles, nerves and blood vessels hence they are not related to bone dislocation.
The correct option is (c)- Ligament break

Question:7

While doing work and running, you move your organs like hands, legs etc.Which among the following is correct?
(a) Smooth muscles contract and pull the ligament to move the bones
(b) Smooth muscles contract and pull the tendons to move the bones
(c) Skeletal muscles contract and pull the ligament to move the bones
(d) Skeletal muscles contract and pull the tendon to move the bones
Answer- (d)
Solution- All the statements are incorrect except the statement (d) Skeletal muscles contract and pull the tendon to move the bones.
Smooth muscles are located in organs like the urinary bladder, uterus, respiratory tract, etc. These muscles are not connected to bones and do not function in movements like walking and running. Skeletal muscles attach directly to the skeleton which causes the movement of muscles with bones. The skeletal muscles are attached to bones by tendons. When the skeletal muscles contract, it pulls the tendon attached to the bone, leading to the movement of bones.
The correct option is (d) Skeletal muscles contract and pull the tendon to move the bones

Question:8

Which muscles act involuntarily?
(i) Striated muscles
(ii) Smooth muscles
(iii) Cardiac muscles
(iv) Skeletal muslces
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer- (b)
Solution: Skeletal muscles are attached to the bones which function in movements like, walking, running, etc. These are voluntary movements and are under the direct control of an individual. Skeletal muscles are also striated muscles.
On the other hand, smooth muscles are located in the organs of the body like urinary bladder, uterus, respiratory tract, etc. They are involuntary in nature. Cardiac muscles are present in the heart and help in the rhythmic contraction and relaxation of heart which is an involuntary action.
The correct option is (b) (ii) and (iii)

Question:9

Meristematic tissues in plants are
(a) localised and permanent
(b) not limited to certain regions
(c) localised and dividing cells
(d) growing in volume
Answer - (c)
Solution: Meristematic tissue is made up of living cells. They have the capability to divide actively. The growth in plants is restricted to certain regions because meristematic cells are localised and not distributed throughout the plant body. The growth due to meristematic cells occurs by an increase in number of cells and not by increase in volume of existing cells.
The correct option is (c) localised and dividing cells

Question:10

Which is not a function of epidermis?
(a) Protection from adverse condition
(b) Gaseous exchange
(c) Conduction of water
(d) Transpiration
Answer- The correct option is (c) Conduction of water
Solution- Epidermis forms the outer layers of different parts of plant like leaves, flowers, roots, stem etc. They are made up of a single layer of cells and help in protection from adverse conductions, gaseous exchange and transpiration.
Xylem carries out the conduction of water and minerals in plants. Thus conduction of water is not a function of the epidermis.

Question:11

Select the incorrect sentence
(a) Blood has matrix containing proteins, salts and hormones
(b) Two bones are connected with ligament
(c) Tendons are non-fibrous tissue and fragile
(d) Cartilage is a form of connective tissue
Answer-(c)
Solution- Blood consists of red blood cells, white blood cells and platelets suspended in a fluid matrix containing proteins, salts and hormones. Ligaments connect two bones together in joints.Tendon is a tough, fibrous connective tissue, which connects muscle to bone. Tendons have great strength.Cartilage is a flexible connective tissue having widely spaced cells. They are found in many areas of the body like joints, end of the ribs etc.
The correct option is (c) Tendons are non-fibrous tissue and fragile

Question:12

Cartilage is not found in
(a) nose
(b) ear
(c) kidney
(d) larynx
Answer- (c)
Solution- Cartilage is a connective tissue found in nose, pinna of the ear and larynx. They provide support and flexibility to various parts of our body but not in the kidney. Kidneys help in the process of excretion and consists of renal tubules.
The correct option is (c) kidney

Question:13

Fats are stored in human body as
(a) cuboidal epithelium
(b) adipose tissue
(c) bones
(d) cartilage
Answer- (b)
Solution- Cuboidal epithelium forms the lining in the digestive tract and helps in excretion and secretion. Bones and cartilage are specialized connective tissue and provide support to the bodyAdipocytes are the cells which store fats and these are present in adipose tissue. Adipose tissue is present below the layers of skin and act as an insulating layer by reducing the loss of heat through the skin.
The correct option is (b) adipose tissue

Question:14

Bone matrix is rich in
(a) Fluoride and calcium
(b) Calcium and phosphorus
(c) Calcium and potassium
(d) Phosphorus and potassium
Answer- (b)
Solution- The bone cells are present in a hard matrix. The primary tissue of bone, osseous tissue, is hard and lightweight made up of salts of calcium and phosphate. The matrix is deposited in form of concentric layers of lamellae around a central aversion canal. The bone cells occupy small spaces between the concentric layers of matrix.
The correct option is (b) calcium and phosphorus

Question:15

Contractile proteins are found in
(a) bones
(b) blood
(c) muscles
(d) cartilage
Answer- (c)
Solution- Muscles show the property of contraction and relaxation. This property is because of the presence of contractile proteins in them. Bones and cartliage contain protein collagen while blood contains serum albumin and globulin.
The correct option is (c) muscles

Question:16

Voluntary muscles are found in
(a) alimentary canal
(b) limbs
(c) iris of the eye
(d) bronchi of lungs
Answer- (b)
Solution- Voluntary muscles are under the control of a person. Skeletal muscles are voluntary in nature and found in the limbs of the body. Alimentary canal, iris of the eye and bronchi of lungs contain involuntary muscles and are not under the control of a person.
The correct option is (b) limbs

Question:17

Nervous tissue is not found in
(a) brain
(b) spinal cord
(c) tendons
(d) nerves
Answer- (c)
Solution- Neurons are the nerve cells that form nervous tissue and it is found in the nervous system. Brain and spinal cord form a part of the CNS and nerves form a part of the PNS. Tendons are found in joints of a bone and muscles and are made up of collagen. It doesn’t form the part of the nervous system.
The correct option is (c) tendons

Question:18

Nerve cell does not contain
(a) axon
(b) nerve endings
(c) tendons
(d) dendrites
Answer- (c)
Solution- Nerve cells are also called as neurons. Axons, nerve endings and dendrites form the nerve cell.Tendons are found in joints of a bone and muscles and made up of collagen. It doesn’t form the part of the nervous system.
The correct option is (c) tendons

Question:19

Which of the following helps in repair of tissue and fills up the space inside the organ?
(a) Tendon
(b) Adipose tissue
(c) Areolar
(d) Cartilage
Answer- (c)
Solution- Areolar tissue is a connective tiisue which helps in repair and fills up space inside the organs. It is found between the skin and muscles and also in the bone marrow. The ground substance of areolar tissue fills all of the spaces between the cells and fibres. The areolar tissue present on the skin binds the outer layers of the skin to the muscles present beneath it.
The correct option is (c) Areolar

Question:20

The muscular tissue which function throughout the life continuously without fatigue is
(a) skeletal muscle
(b) cardiac muscle
(c) smooth muscle
(d) voluntary muscle
Answer (b)
Solution- Skeletal muscle, smooth muscle and voluntary muscles work as and when required.Cardiac muscles found in the walls of the heart are involuntary in nature. They have a uniquie structure. Cardiac muscles are highly resistant to fatigue because of the presence oflarge number of mitochondria which enables continuous aerobic respiration and a blood supply which provides nutrients and oxygen to the muscles.
The correct option is (b) cardiac muscle

Question:21

Which of the following cells is found in the cartilaginous tissue of the body?
(a) Mast cells
(b) Basophils
(c) Osteocytes
(d) Chondrocytes
Answer (d)
Solution- The mast cells is a granulocyte, found in areolar tissue. Basophils provide immunity and are a type of WBC. Osteocytes are cells found in the bones. Chondrocytes are found in the cartilaginous tissue of the body involed in producing and maintaning the cartilaginous matrix.
The correct option is (d) Chondrocytes

Question:22

The dead element present in the phloem is
(a) companion cells
(b) phloem fibres
(c) phloem parenchyma
(d) sieve tubes
Answer (b) Phloem fibres
Solution: Phloem is a complex tissue and forms a part of the vascular bundle. The phloem consists of sieve tubes, phloem parenchyma and phloem fibres. Phloem fibres possess narrow lumen and are thick-walled, elongated spindle-shaped dead cells. They provide the tensile strength and mechanical support to the tissue. Phloem parenchyma consists of thin-walled living cells of parenchyma. They help in storage and lateral food conduction. Except for phloem fibres, other phloem cells are living cells.
The correct option is (b) Phloem fibres

Question:23

Which of the following does not lose their nucleus at maturity?
(a) Companion cells
(b) Red blood cells
(c) Vessel
(d) Sieve tube cells
Answer (a)
Solution- Red blood cells lose the nucleus at they get mature. The process of erythropoiesis forms them. The vessel loses its nucleus on attaining maturity. Sieve tube cells also lose their nucleus and many cell organelles upon maturity. Companion cells are connected to the sieve tube through plasmodesmata. These cells are metabolically active and sieve tube elements are dependent on these cells. So, they do not lose their nucleus at maturity.
The correct option is (a) Companion cells

Question:24

In desert plants, rate of water loss gets reduced due to the presence of
(a) cuticle
(b) stomata
(c) lignin
(d) suberin
Answer (a) cuticle
Solution- The cuticle is present in desert plants. It is a protective waxy layer covering the epidermis of the leaf, young shoots and other aerial parts of a plant. The presence of cuticle prevents the water loss from the plant. Stomata are the openings that help in the process of transpiration.
Lignin hardens the cell wall and provides flexibility and tensile strength to the cell wall. Suberin is present in cork cells and makes the cells impervious to water.
The correct option is (a) cuticle

Question:25

A long tree has several branches. The tissue that helps in the sideways conduction of water in the branches is
(a) collenchyma
(b) xylem parenchyma
(c) parenchyma
(d) xylem vessels
Answer (b)
Solution- Collenchyma is a supportive tissue and has no role in the conduction of water. Xylem is a complex permanent tissue that consists of tracheids, vessels and parenchyma. Xylem parenchyma helps in the sideways conduction of water, while xylem vessels and tracheids help in the vertical conduction of water.
The correct option is (b) xylem parenchyma

Question:26

If the tip of a sugarcane plant is removed from the field, it keeps on growing in length. It is due to the presence of
(a) cambium
(b) apical meristem
(c) lateral meristem
(d) intercalary meristem
Answer- (d)
Solution:
The meristems that are present in stems at the base of nodes and leaf blades are called an intercalary meristem. These can keep on dividing and form new cells. Thus, they are responsible for the longitudinal growth of the plant, hence the length of the sugarcane keep on increasing.
The correct option is (d) intercalary meristem

Question:27

A nail is inserted in the trunk of a tree at a height of 1 metre from the ground level. After 3 years the nail will
(a) move downwards
(b) move upwards
(c) remain at the same position
(d) move sideways
Answer (c)
Solution:
The growth in the plants is because of the presence of meristematic tissue. The apical meristem is located on the tip of the root and shoot. If we insert a nail in the trunk of a tree at a height of 1 metre from the ground, even after 3 years, the nail remains at the same level. It will not change its position as the apical meristem responsible for growth (length) is present in the apices only, and the lateral meristem responsible for the increase in girth will lead to no change in length.
The correct option is (c) remain at the same position

Question:28

Parenchyma cells are
(a) Relatively unspecified and thin walled
(b) Thick walled and specialised
(c) Lignified
(d) None of these
The answer is (a)
Solution:
Parenchyma is a type of simple permanent tissue. It forms the bulk of the plant body. It is made up of living cells which are unspecialised and have thin cell walls. The cells are loosely arranged, thus large spaces between cells (intercellular spaces) are found in this tissue.
The correct option is (a) relatively unspecified and thin-walled.

Question:29

Flexibility in plants is due to
(a) collenchyma
(b) sclerenchyma
(c) parenchyma
(d) chlorenchyma
Answer (d)
Solution- Collenchyma provides flexibility to the plants. It is present in the leaf stalk below the epidermis and allows bending of various parts of a plant-like tendrils and stems of climbers without breaking. Thus, it provides mechanical support also.
The correct option is (d) collenchyma

Question:30

Cork cells are made impervious to water and gases by the presence of
(a) cellulose
(b) lipids
(c) suberin
(d) lignin
Answer- (c)
Solution-
Cellulose is present in the cell walls of plants. The plasma membrane is selectively permeable, and it is not impervious to water. Lignin acts as a cement and helps in the hardening of the cell wall. The thin walls of the cork cells are saturated with an organic waxy substance, suberin. It makes cork almost impervious to water and air.
The correct option is (c) suberin

Question:31

Survival of plants in the terrestrial environment has been made possible by the presence of
(a) intercalary meristem
(b) conducting tissue
(c) apical meristem
(d) parenchymatous tissue
Answer (b)
Solution:
The conducting tissues present in plants are the xylem and phloem. These are responsible for the survival of plants in the terrestrial environment. Xylem helps in the conduction of water from roots to all the parts of the plants and phloem transports food and other nutrients from leaves to other parts of the plant.
The correct option is (b) conducting tissue

Question:32

Choose the wrong statement
(a) The nature of the matrix differs according to the function of the tissue
(b) Fats are stored below the skin and in between the internal organs
(c) Epithelial tissues have intercellular spaces between them
(d) Cells of striated muscles are multinucleate and unbranched
Answer- (c)
Solution- The statement (c) is wrong. Epithelial tissues do not have any intercellular spaces between them. They are tightly bound to each other and make a continuous sheet or layer of cells.
The correct option is (c) Epithelial tissues have intercellular spaces between them

Question:33

The water conducting tissue generally present in gymnosperm is
(a) vessels
(b) sieve tube
(c) tracheids
(d) xylem fibres
Answer- (c)
Solution:
Vessels are absent in gymnosperms. Sieve tubes are present in phloem and form a part of the phloem and have no role in the conduction of water. Xylem fibres provide structural rigidity and have no role in the conduction of water. The water-conducting tissue present in gymnosperm is tracheids. These are elongated dead cells with hard, lignified walls. They conduct water and do not have open ends like the vessels.
The correct option is – (c) tracheids

Short Answer NCERT Exemplar Class 9 Science Chapter 6

Question:34

Animals of colder regions and fishes of cold water have thicker layer of subcutaneous fat. Describe why?
Answer:

The animals and fishes that are found in the colder regions or cold water have a thicker layer of subcutaneous fat. This layer acts as an insulator and prevents heat loss from the body. This fat layer also stores food which can be used by the body during the scarcity of food, Thus, it will help the animals in resisting to low temperature in cold climates.

Question:35

Match the column (A) with the column (B)
(A) (B)
(a) Fluid connective tissue (i) Subcutaneous layer
(b) Filling of space inside the organs (ii) Cartilage
(c) Striated muscle (iii) Skeletal muscle
(d) Adipose tissue (iv) Areolar tissue
(e) Surface of joints (v) Blood
(f) Stratified squamous epithelium (vi) Skin

Answer- a- v, b- iv, c- iii, d-I, e- ii, f- vi
a.Blood is a fluid connective tissue made up of cells and an extracellular matrix. The extracellular matrix is made of protein, polysaccharide matrix.
b.Areolar tissue helps in filling of space inside the organs. It is found in between skin and muscles, around blood vessels, neurons and also in bone marrow.
c.Skeletal muscle is called as striated muscle also. They have a specific pattern of repeating sarcomere. Sarcomere is the basic unit of muscle. Striated muscle are voluntary in nature.
d.The Subcutaneous layer consists of adipose tissue. Adipose tissue is a type of connective tissue which helps in storing fat. It is located below the skin and also act as an insulator.
e.Cartilage is present on the surface of joints. Cartilage is a type of connective tissue in which solid matrix is made of protein and sugars. It makes the joint surface smooth.
f.Skin consists of Stratified squamous epithelium. These cells are thin and flat and form a delicate lining. It helps in protecting the body.

Question:36

Match the column (A) with the column (B)
(A) (B)
(a) Parenchyma (i) Thin walled, packing cells
(b) Photosynthesis (ii) Carbon fixation
(c) Aerenchyma (iii) Localized thickenings
(d) Collenchyma (iv) Buoyancy
(e) Permanent tissue (v) Sclerenchyma
Answer: a- i, b- ii, c- iv, d-iii, e- v
a.Parenchyma are thin-walled, packing cells. Their shape changes as per function. They are often present in soft parts of plants.

b.Photosynthesis helps in the fixation of atmospheric Carbon. Photosynthesis is the process in which carbon dioxide and water is taken up by plant and converted to carbohydrates in the presence of sunlight.
c.Aerenchyma- provides Buoyancy. It is present in many aquatic plants. They have large air cavities that enable them to float in water.
d. Collenchyma are Localized thickenings. These cells are living, elongated and irregularly thickened at corners with less intercellular space. It allows easy bending of plant parts without breaking.
e.Sclerenchyma is a type of Permanent tissue. Permanent tissues has lost the ability to divide.. Sclerenchyma cells are dead, long, thin and narrow with thickened walls without any intercellular space. This tissue makes plant hard and stiff.

Question:37

If a potted plant is covered with a glass jar, water vapours appear on the wall of glass jar. Explain why?
Answer:

The water vapours appear on the wallof the glass jar because of a process called transpiration. In this process, the water is released from the plants in the form of vapours through the pore like structures called stomata which are present on the leaves.

Question:38

Name the different components of xylem and draw a living component?
Answer:

Xylem is a complex permanent tissue. It consists of tracheids, vessels, xylem parenchyma and xylem fibres. The only living component present in the xylem is xylem parenchyma. All other components are dead and lignified.

Question:39

Draw and identify different elements of phloem.
Answer:

The phloem is a complex permanent tissue. It helps in the conduction of food and other organic substances from leaf to all other parts of the plant. It is mainly composed of sieve tubes, companion cells, phloem parenchyma, and phloem fibers

Question:40

Write true (T) or false (F)
(a) Epithelial tissue is protective tissue in an animal body.
(b) The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue.
(c) Epithelial cells have a lot of intercellular spaces.
(d) Epithelial layer is a permeable layer.
(e) Epithelial layer does not allow regulation of materials between body and external environment.
Answer:

a. True. The epithelial tissue consists of the protective layer of cells which covers the surface of the body.
b. True. Epithelial tissue is present as a lining of blood vessels, lung alveoli and kidney tubules
c. False. The epithelial cells are closely packed and do not have any intercellular spaces
d. True. The epithelial cells are permeable in nature because they allow the movement of substances between the body and external environment.
e. False. The epithelial cells help in the movement of substances between the body and external environment.

Question:41

Differentiate between voluntary and involuntary muscles. Give one example of each type.
Answer:

Question:42

Differentiate the following activities on the basis of voluntary (V) or involuntary (I V) muscles.
(a) Jumping of frog
(b) Pumping of the heart
(c) Writing with hand
(d) Movement of chocolate in your intestine
Answer:

a-V, b-IV, c-V, d-IV
(a) Jumping of frog – It is an activity of voluntary muscles and involves the limbs of the frog.
(b) Pumping of the heart- a function of involuntary muscles and involves cardiac muscles.
(c) Writing with the hand is a function of voluntary muscles and involves the hind limbs of humans.
(d) Movement of chocolate in your intestines is a function of involuntary muscles and involves smooth muscles of the alimentary canal.

Question:43

Fill in the blanks
(a) Lining of blood vessels is made up of———.
(b) Lining of small intestine is made up of ———.
(c) Lining of kidney tubules is made up of———.
(d) Epithelial cells with cilia are found in———of our body.
Answer:

a. Lining of blood vessels is made up of squamous epithelium
b. The lining of small intestine is made up of columnar epithelium
c. The lining of kidney tubules is made up of cuboidal epithelium
d. Epithelial cells with cilia are found in respiratory tract of our body

Question:44

Water hyacinth float on water surface. Explain.
Answer:

Water hyacinth is a blue violet colored flowers which consists of air-filled tissues that provides buoyancy and allows them to float on the water. Thetissues present in them are called as aerenchyma. It is a type of parenchyma tissue.

Question:45

Which structure protects the plant body against the invasion of parasites?
Answer:

The epidermis is the outermost layer and protects the plant body against the invasion of parasites. It has thick cuticle and dermal tissue which help in preventing the attack from parasites.

Question:46

Fill in the blanks
(a) Cork cells possesses———on their walls that makes it impervious to gases and water.
(b) ——— have tubular cells with perforated walls and are living in nature.
(c) Bone possesses a hard matrix composed of———and ———.
Answer:

(a) Cork cells possess Suberin on their walls that makes it impervious to gases and water.
(b) Sieve tubes have tubular cells with perforated walls and are living in nature.
(c) Bone possesses a hard matrix composed of calcium and Phosphorus.

Question:47

Why is epidermis important for the plants?
Answer:

The epidermis is made up of a single layer of continuous cells. It reduces water loss from the plant. The epidermal cell present on the aerial parts of the plant often secretes a waxy, water-resistant layer on their outer surface, which provides protection against loss of water, mechanical injury and invasion by parasitic fungi

Question:48

Fill in the blanks
(a) ———are forms of complex tissue.
(b) ———have guard cells.
(c) Cells of cork contain a chemical called———
(d) Husk of coconut is made of ———tissue.
(e) ———gives flexibility in plants.
(f) ———and———are both conducting tissues.
(g) Xylem transports———and———from soil.
(h) Phloem transport———from———to other parts of the plant
Answer:

a. Xylem and Phloem
b. Stomata
c. Suberin
d. Sclenchyma
e. Collenchyma
f. Xylem;Phloem
g. Water and minerals
h. Food, leaf

NCERT Exemplar Class 9 Science Solutions Chapter 6 Long Answer

Question:49

Differentiate between sclerenchyma and parenchyma tissues. Draw well labelled diagram.
Ans-

The differences between sclerenchyma and parenchyma tissues are-

Question:50

Describe the structure and function of different types of epithelial tissues. Draw diagram of each type of epithelial tissue.
Answer:

Epithelial tissues form the outermost covering in the plant body. It act as a protective tissue. Most organs and cavities present within the body are covered by epithelium. E.g., Skin, lining of the mouth, lining of blood vessels, lung alveoli etc.
The cells of this tissue are tightly packed and form a continuous layer. They have no intercellular spaces between them. They are permeable and play an important role in regulating the exchange of materials between the body and the external environment and also between different parts of the body. All types of epithelial tissue are usually separated from the underlying tissue by an extracellular fibrous basement membrane.
The different types of epithelial tissues are-

(1) Simple squamous epithelium
(2) Stratified squamous epithelium
(3) Columnar epithelium
(4) Ciliated columnar
(5) Cuboidal epithelium
(6) Glandular epithelium

Question:51

Draw well-labelled diagrams of various types of muscles found in human body.
Answer:

Types of muscles in the human body

Skeletal Muscle- These muscles are attached to the skeleton and help in its movement.These muscles are voluntary in nature. They are also known as striated muscles because of the presence of alternate patterns of light and dark bands.
Smooth Muscle- These are non-striated, involuntary muscles controlled by the Autonomous Nervous System. It plays a role in the digestive, urinary, and reproductive systems.
Cardiac Muscle- These are found only in the heart. These are involuntary muscles and help in the pumping of the blood.

Question:52

Give reasons for
(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
(b) Intercellular spaces are absent in sclerenchymatous tissues.
(c) We get a crunchy and granular feeling when we chew pear fruit.
(d) Branches of a tree move and bend freely in high wind velocity.
(e) It is difficult to pull out the husk of a coconut tree.
Answer:

a) Meristamatic tissue cells divide continuously and have a prominent nucleus and dense cytoplasm. As they are diving continuously, they need not store food or waste products hence, they lack vacuoles.
b) Sclerenchyma doesn’t contain intercellular spaces because its cell wall is lignified. These are densely packed and provide protection to the plant and mechanical strength.
c) The cruncy and granular feeling upon chewing the pear fruit is because of sclerenchyma tissue. The sclerenchyma cells are of two types- fibres and sclereids. The sclereids give a crunchy feeling to the pear fruit because it provides support and harden the tissue
d) The branches of a tree move and bend freely in high wind velocity because of the presence of collenchyma that adds the property of flexibility.
e) It is difficult to pull out the husk of a coconut tree because it is made up of sclerenchyma tissues which are dead cells. This gives rigidity and stiffness.

Question:53

List the characteristics of cork. How are they formed? Mention their role.
Answer-
The characteristics of cork cells are-

• They are mature and dead.

• They are compactly arranged.

• They possess a chemical substance called suberin in their walls.

• They do not have intercellular spaces.

• They are thick and made up of several layers.

As the plants grow older, the outer protective tissue undergoes some changes. In the stem, the epidermis is replaced by a secondary meristem called cork cambium. It is a simple tissue which consists of rectangular cells and vacuolated protoplasts.
Cork cambium forms cork on the outer side and a secondary cortex on the inner side by producing new cells on both sides.
Cork cells are compactly arranged dead cells which lack intercellular spaces. The cell walls of cork cells are thickened by a substance called suberin (fat) which makes these cells impermeable to water and gases.
Role-
It provides protection to plants and prevents water loss.
It also protects the plants from infection and mechanical injury.
Cork is used as an insulator because it is light in weight and doesn’t catch fire.

Question:54

Why are xylem and phloem called complex tissues? How are they different from one other?
Answer:

Tissues are of different types- simple and complex. A complex tissue consists of more than one type of cells having a common origin which coordinate to perform a common function. Xylem and phloem are called complex tissues because they are made up of different types of cells.
Xylem consists of four different types of elements-

1. tracheids

2. vessels

3. xylem parenchyma

4. xylem sclerenchyma
   The phloem also consists of four different types of elements-

5. sieve tubes

6. companion cells

7. phloem parenchyma

8. phloem fibre
   The basic difference between xylem and phloem is-

Question:55

(a) Differentiate between meristematic and permanent tissues in plants
(b) Define the process of differentiation
(c) Name any two simple and two complex permanent tissues in plants.
Answer:

a) Meristematic tissues and Permanent tissues differ in the following way-

(b) The process by which the cells divide meristematically and take a permanent shape, size and function is called differentiation. The differntiated cells take up specific roles, lose their ability to divide and form permanent tissue.
(c) Simple permanent tissue- parenchyma and collenchyma Complex permanent tissue- xylem and phloem.