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NCERT Exemplar Class 12 Biology Solutions Chapter 16 Environmental Issues

NCERT Exemplar Class 12 Biology Solutions Chapter 16 Environmental Issues

Edited By Priyanka kumari | Updated on Aug 26, 2022 05:55 PM IST | #CBSE Class 12th

NCERT exemplar Class 12 Biology solutions chapter 16 - Environmental Issues, is the need of the hour. The environmental issue is a collective term used for the aftermath of imbalance caused to the environment. This imbalance occurs due to various causes, and this chapter of NCERT aims to explore these causes such as air pollution, water pollution and also tries to provide preventive measures. NCERT exemplar Class 12 Biology solutions chapter 16 is very helpful when preparing for CBSE board exams. To make it more convenient you can use the NCERT exemplar Class 12 Biology solutions chapter 16 pdf download function to make learning easier.
Also, read NCERT Solutions for Class 12 Biology

NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues

Multiple Choice Questions:

Question:1

Non-biodegradable pollutants are created by:
a. nature
b. excessive use of resources
c. humans
d. natural disasters

Answer:

The answer is the option (c) humans
Explanation: Human beings create and use various non-biodegradable substances and end up creating various kinds of pollution in the process.

Question:2

According to the Central Pollution Control Board, the diameter of particles that are responsible for causing great harm to human health is:
a. 2.5-micrometre
b. 5.0-micrometer
c. 10.0-micrometer
d. 7.5 micrometre

Answer:

The answer is the option (a) 2.50 micrometers

Question:3

The material generally used for soundproofing of rooms like a recordingstudio and auditorium is:
a. cotton
b. coir
c. wood
d. Styrofoam

Answer:

The answer is the option (d) Styrofoam
Explanation: (d) Styrofoam prevents reflection of sound waves instead, it absorbs them after their collision.

Question:4

Compressed Natural Gas (CNG) is:
a. propane
b. methane
c. ethane
d. butane

Answer:

The answer is the option (b) methane

Question:5

World’s most problematic aquatic weed is:
a. Azolla
b. Wolffia
c. Eichhornia
d. Trapa

Answer:

The answer is the option (c) Eichhornia
Explanation: Eichhornia is commonly known as water hyacinth and has been the most notorious aquatic weed found all over the world.

Question:6

Which of the following exhibits biomagnification?
a. SO2
b. Mercury
c. DDT
d. Both b & c

Answer:

The answer is the option (d) Both (b) & (c)
Explanation: Biomagnification is well known reason and result of chemicals like: Mercury and DDT.

Question:7

The expanded form of DDT is:
a. dichloro diphenyl trichloroethane
b. dichloro diethyl trichloroethane
c. dichloro dipyridyl trichloroethane
d. dichloro diphenyl tetrachloroacetate

Answer:

The answer is the option (a) dichloro diphenyl trichloroethane
Explanation: (a) dichloro diphenyl trichloroethane according to its structural formula.

Question:8

Which of the following material takes the longest time for biodegradation?
a. Cotton
b. Paper
c. Bone
d. Jute

Answer:

The answer is the option (c) Bone
Explanation: This is the reason why bones of humans and animals have been found from prehistoric period.

Question:9

Choose the incorrect statement.
a. The Montreal protocol is associated with the control of emission of ozone-depleting substances
b. Methane and carbon dioxide are greenhouse gases
c. Dobson units are used to measure the oxygen content of air
d. Use of incinerators is crucial to disposal of hospital wastes

Answer:

The answer is the option (c) Dobson units are used to measure oxygen content
Explanation: Dobson is the unit used to measure the thickness of ozone in air column.

Question:10

Among the following which one causes maximum indoor chemicalpollution?
a. burning coal
b. burning cooking gas
c. burning mosquito coil
d. room spray

Answer:

The answer is the option (a) burning coal
Explanation: Burning of coal produces lot of carbon dioxide because solid fuel does not burn as efficiently as liquid or gaseous fuels.

Question:11

The green scum seen in the freshwater bodies is:
a. blue-green algae
b. red algae
c. green algae
d. both (a) and (c)

Answer:

The answer is the option (d) both (a) and (c)

Question:12

The loudness of a sound that a person can withstand without discomfortis about
a. 150 dB.
b. 215 dB.
c. 30 dB.
d. 80 dB

Answer:

The answer is the option (d) 80 dB.

Question:13

The major source of noise pollution worldwide is due to:
a. office equipment
b. transport system
c. sugar, textile and paper industries
d. oil refineries and thermal power plants

Answer:

The answer is the option (b) transport system
Explanation: With the advent of progressing trade, commerce, and industry the means and the usage of transport has also increased. Be any trade or industry, transport is the final step for its execution.

Question:14

Match the following and choose the correct option

Column IColumn II
A. Environment Protection Acti. 1974
B. Air Prevention & Control of Pollution Actii. 1987
C. Water Actiii. 1986
D. Amendment of Air Act to include noise as an air pollutantiv. 1981
The correct matches is;
a. A-iii, B-iv, C-i, D-ii
b. A-i, B-iii, C-ii, D-iv
c. A-iv, B-i, C-ii, D-iii
d. A-iii, B-iv, C-ii, D-i

Answer:

The answer is the option (a) (i)-(C), (ii)-(D), (iii)-(A), (iv)-(B)
Explanation: (a) (i)-(C), (ii)-(D), (iii)-(A), (iv)-(B)

Question:15

Catalytic converters are fitted into automobiles to reduce the emission ofharmful gases. Catalytic converters change unburnt hydrocarbons into:
a. carbon dioxide and water
b. carbon monoxide
c. methane
d. carbon dioxide and methane

Answer:

The answer is the option (a) carbon dioxide and water
Explanation: Carbon monoxide is a lethal gas even in low concentration and hence option ‘b’ is incorrect. Methane is hydrocarbon and hence options ‘c’ and ‘d’ are ruled out.

Question:16

Why is it necessary to remove sulphur from petroleum products?
a. To reduce the emission of sulphur dioxide in exhaust fumes
b. To increase the efficiency of automobiles engines
c. To use sulphur removed from petroleum for commercial purposes
d. To increase the life span of engine silencers

Answer:

The answer is the option (a) To reduce the emission of sulphur dioxide in exhaust fumes

Question:17

Which one of the following impurities is easiest to remove from wastewater?
a. Bacteria
b. Colloids
c. Dissolved solids
d. Suspended solids

Answer:

The answer is the option (d) Suspended solids
Explanation: Suspended solids can be removed by sedimentation and decantation. Dissolved solids can be removed by evaporation of water which is an energy intensive process. Removal of colloids needs centrifugation. Removal of bacteria involves use of bactericidal agents.

Question:18

Which one of the following diseases is not caused due to contamination of water?
a. Hepatitis-B
b. Jaundice
c. Cholera
d. Typhoid

Answer:

The answer is the option (a) Hepatitis-B
Explanation: Hepatitis B is spread through body fluids; like blood, sperm, sputum, mucus, etc.

Question:19

Nuisance growth of aquatic plants and bloom-forming algae in natural waters are generally due to high concentrations of:
a. carbon
b. sulphur
c. calcium
d. phosphorus

Answer:

The answer is the option (d) phosphorus

Question:20

Algal blooms impart a distinct colour to water due to:
a. their pigments
b. excretion of coloured substances
c. formation of coloured chemicals in water facilitated by physiological degradation of algae.
d. absorption of light by an algal cell wall.

Answer:

The answer is the option (a) their pigments
Explanation: If green algae are prevalent, they impart green color to water. Red algae impart red color and brown algae impart brown color.

Question:21

Match the items in column I and column II and choose the correct option:

Column IColumn II
A. UVi. Biomagnification
B. Biodegradable Organic matterii. Eutrophication
C. DDTiii. Snow blindness
D. Phosphatesiv. BOD
The correct match is:
a. A-ii, B-i, C-iv, D-iii
b. A-iii, B-ii, C-iv, D-i
c. A-iii, B-iv, C-i, D-ii
d. A-iii, B-i, C-iv, D-ii

Answer:

The answer is the option (c) A (iii), B (iv), C (i), D (ii)

Very Short Answer Type Questions:

Question:1

Use of lead-free petrol or diesel is recommended to reduce the pollutants emitted by automobiles. What role does leadership play?

Answer:

The lead in the petrol deactivates the catalysts and causes the emission of unburnt hydrocarbons into the atmosphere resulting in air pollution.

Question:2

In which year was the Air (Prevention and Control of Pollution) Act amended to include noise as air pollution.

Answer:

The Air (Prevention and Control of Pollution) Act came into force in the year 1981 and was amended in 1987 to include noise as an air pollutant.

Question:3

Name the city in our country where the entire public road transport runs on CNG.

Answer:

By the end of the year 2002 in New Delhi, the entire transport runs on CNG.

Question:4

It is a common practice to undertake desilting of the overhead water tanks. What is the possible source of silt that gets deposited in the water tanks?

Answer:

Presence of suspended impurities; like sand and clay causes siltation in water tanks since the water supply is drawn to overhead tanks from sources like river, deep bore well etc.

Question:5

What is cultural eutrophication?

Answer:

Cultural eutrophication is a form of water pollution. When eutrophication is accelerated due to human activities; it is called cultural eutrophication. For example, the addition of excessive fertilizers into lakes or effluents from industries results in cultural eutrophication.

Question:6

List any two adverse effects of particulate matter on human health.

Answer:

Following are the two adverse effects of particular matter on human health:
(a) Asthma
(b) Respiratory tract infection

Question:7

What is the raw material for polyblend?

Answer:

Polyblends are the natural man-made fibres which are made by a mixture of 2 or more polymers. The raw material for polyblend is polythene.

Question:8

Blends of polyblend and bitumen, when used, help to increase road life by a factor of three. What is the reason?

Answer:

Addition of polyblend to bitumen while laying the roads enhances water repellant property of bitumen. Thus, it increases road life by a factor of three.

Question:9

Mention any two examples of plants used as windbreakers in the agricultural fields.

Answer:

Hedge, Jamun, Imli, Neem, Babul, Eucalyptus are some of the plants that can be used as windbreakers in the agricultural fields.

Question:10

Name an industry which can cause both air and thermal pollution and as well as eutrophication.

Answer:

Fertilizer industry can cause both air and thermal pollution as well as eutrophication.

Question:11

What is an algal bloom?

Answer:

Excessive growth of free-floating algae on water bodies due to their nutrient enrichment is called an algae bloom.

Question:12

What do you understand by biomagnification?

Answer:

When a particular substance is passed on through various trophic levels; its concentration of the toxic substances increases at every step. This phenomenon is called biomagnification.

Question:13

What are the three major kinds of impurities in domestic wastewater?

Answer:

Following are the three major kinds of impurities in domestic wastewater.
(a) Suspended impurities like sand and silt.
(b) Colloidal materials like bacteria, faeces, cloth etc.
(c) Dissolved materials like nutrients (nitrates, phosphates, sodium, calcium)

Question:14

What is reforestation?

Answer:

Restoring a previously existing forest is called reforestation. The intervention of human beings can help in the process.

Question:15

What is the best solution for the treatment of electronic wastes?

Answer:

Recycling is an environmentally friendly manner is the best solution for the treatment of electronic wastes. They can recycle 95-98% by weight.

Short Answer Type Questions:

Question:1

Is it true that carpets and curtains/drapes placed on the floor or wall surfaces can reduce noise level? Explain briefly?

Answer:

Yes, It is true that carpets and curtains/drapes placed on the floor or wall surfaces can reduce the noise level. These objects are made of fibres and fibres act as sound absorber by reducing the noise level.

Question:

What is hybrid vehicle technology? Explain its advantages with a suitable example?

Answer:2

Hybrid vehicle technology involves allowing the vehicle to run on a dual-mode like the use of the gasoline-run engine and battery-powered engine in the same vehicle.
Gasoline-operated motor charged the battery and battery drives the vehicle. Hybrid vehicle helps in significantly reducing the consumption of gasoline and thus helps in reducing air pollution.

Question:3

Is it true that if the dissolved oxygen level drops to zero, the water will become septic? Give an example which could lower the dissolved oxygen content of an aquatic body.

Answer:

It is true that if the dissolved oxygen level drops to zero, the water will become septic. When this happens, many aquatic animals die because they do not get any dissolved oxygen to breathe. When sewage is discharged into a water body, microorganisms feed on organic impurities. In this process, they consume most of the oxygen present in water. This reduces the level of dissolved oxygen to negligible level.

Question:4

Name anyone greenhouse gas and its possible source of production on a large scale. What are the harmful effects of it?

Answer:

Carbon dioxide is one of the most common and potent greenhouse gas. It is produced by the burning of fossil fuels and other organic materials. Harmful effects of the increase in greenhouse gases include the melting of glaciers, respiratory problems in human beings, excessive temperature, etc. The excess level of carbon dioxide in the atmosphere results in global warming.

Question:5

It is a common practice to plant trees and shrubs near the boundary walls of buildings. What purpose do they serve?

Answer:

Trees and shrubs are effective in reducing the noise level. Planting trees and shrubs near the boundary walls of buildings help in reducing noise level and act as dust catchers and air purifiers apart from adding aesthetic value to the surrounding. Such a decorated line of trees along the boundary or along the roadside is also called a sound barrier.

Question:6

Why has the National Forest Commission of India recommended a relatively larger forest cover for hills than for plains?

Answer:

It is an established fact that conservation efforts in the biodiversity-rich area always give better results. Hills have better biodiversity than plains because of less degree of human intervention. In addition, large forest cover for hills helps in reducing the chances of landslides and soil erosion. This is the reason the National Forest Commission of India has recommended a relatively larger forest cover for hills than for plains.

Question:7

How can slash and burn agriculture become environment friendly?

Answer:

Slash and burn agriculture, also known as jhum cultivation, has been in use since ancient times by tribal people all over the world. Earlier, proper recovery time was allowed for forests to recover when a particular patch of land was left fallow. But due to increased population, this recovery period is often ignored. To make the slash and burn agriculture environment friendly, we need to give adequate recovery time and encourage the use of ashes obtained from burning the plants as fertilizers.

Question:8

What is the main idea behind “Joint Forest Management Concept” introduced by the Government of India?

Answer:

Joint Forest Management Concept was introduced by the Government of India with the objective of involving and motivating the local community in forest management. In the past, it was observed that when the local people were excluded from forest management; they felt alienated. This was because they were robbed of their traditional rights on forests. This resulted in a clash of interests between the government and the local people, and the conservation efforts did not bear results. Involvement of local community produced better results in terms of conservation in a sustainable manner. Generation of employment was an added benefit from the program.

Question:9

What do you understand by snow-blindness?

Answer:

Snow-blindness is also known as photokeratitis. It happens because of exposure of eyes to UV radiation and thus inflamed cornea. Burning sensation, pain, temporary loss of vision and increased tears are common symptoms of snow-blindness.

Question:10

How has DDT caused a decline in the bird population?

Answer:

DDT is an organic compound and is a potent pesticide. The predator birds are at higher risk of having an extremely high level of DDT in their body. DDT is resistant to metabolism by living beings and hence tends to accumulate. The presence of DDT in a bird’s body leads to thinning of eggshells and their premature breaking. This explains the declining population of birds because of DDT.

Question:11

Observe the figure A and B are given below and answer the following questions

i. The power generation by the above two methods is non-polluting True/False.
ii. List any two applications of solar energy
iii. What is a photovoltaic cell?

Answer:

(i) Yes, it is True that both the methods are non- polluting and environment friendly.
(ii) Two applications of solar energy are using solar cells to produce electricity, using solar cooker for cooking food, using a solar heater for hot water.
(iii) A cell, which converts solar energy directly into electric energy by the photovoltaic effect, is known as photovoltaic cell.

Long Answer Questions:

Question:1

Write a short note on electronic waste. List the various sources of e-wastes and the problems associated with its disposal.

Answer:

Electronic waste is the residue of the electronic applications after usage. E-waste contains various metals, like copper, iron, nickel, gold, silver, etc. and plastic. Sources of E-waste: Computers, printers, scanners, webcam, mobile phones, music players, e-reader, etc.
Problems associated with the disposal of e-waste:
  1. Dumping of e-waste will result in accumulation of plastic on land causing soil pollution and sometimes even air pollution.
  2. Extraction of metals; like iron or gold involves the incineration of plastic components which creates many polluting substances.
  3. Manual handling of e-waste can be harmful to workers since it contains many toxic metals.
  4. Most of the developed countries transport over half of their e-waste to the developing countries like India, China and Pakistan. Only the developed nations have facilities advanced enough to recycle e-waste in such huge capacities.

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Question:2

What is organic farming? Discuss the benefits of organic farming as a viable practice in the context of developing nations like India.

Answer:

Organic farming is a method of farming that relies on various methods and inputs so that no synthetic input is used in the process. Green manure or bio-fertilizers are used instead of synthetic fertilizers. Bio-fertilizers include bacteria, fungi, and cyanobacteria. Pesticides and weedicides from natural sources are used, and those from synthetic sources are not used.
Viability of Organic Farming in India:
  1. Organic farming can be highly beneficial in a labour surplus country; like India, because organic farming is highly labour intensive.
  2. Majority of Indian farmers still use cattle for farm operations. This means good availability of raw materials for making green manure is there.
  3. Indian farmers have traditional knowledge of many plants, which have pesticidal, and weedicide properties. This knowledge can be harnessed to get maximum output from organic farming.
  4. Organic farming will also help in reducing soil pollution and groundwater pollution, especially in rural areas.
  5. It is cost-optimized and thus beneficial for the farmers.

Question:3

Waterlogging and soil salinity are some of the problems that have come in the wake of the Green Revolution. Discuss their causes and adverse effects on the environment.

Answer:

Waterlogging and soil salinity are some of the problems that have come in the wake of the green revolution.
Causes of waterlogging and soil salinity:
  1. Many canals were built to implement the Green Revolution. This made for easy availability of water for irrigation. Excess use of water during irrigation results in waterlogging. This draws salt to the soil surface and increases soil salinity.
  2. Also, excess use of fertilizers has led to the accumulation of many unused salts resulting in soil salinity.
Effects of Water Logging:
(a) Increases soil salinity.
(b) Many crops cannot survive in water-logged conditions.
(c) Prolonged period of waterlogging will reduce the number of microorganism and creatures in the soil. This will reduce biodiversity in the soil.
(d) Decomposition of organic matter in stagnant water will release methane, which is a potent greenhouse gas.
Effects of Soil Salinity:
(a) Most of the plants cannot survive in saline soil leading to a reduction in the growth of crops. Root cells get shrunk due to saline water.
(b) Soil will become barren, causing extreme damage to agriculture.
(c) Desertification may take place.

Question:4

What are multipurpose trees? Give the botanical and local names of any two multipurpose trees known to you and list their uses.

Answer:

A tree that can be used for multiple purposes like fruits, shade, timber, medicine, flowers, etc. is called a multipurpose tree. Two multipurpose trees are as follow:
(a) Banana: Musa acuminate
(b) Coconut: Cocos nucifera

Uses of Banana:
  • Fruits are used as food all over the world.
  • Banana flowers are also used as food in many countries.
  • Raw banana is used for making banana chips.
  • Banana leaves are used as platter during a ceremonial feast in India.
  • Banana leaves are also used as packing material.
  • Fibre from the banana stem is used for making textiles.
  • Banana stem is also used for making a makeshift raft.
Uses of Coconut:
  • Fruits are used as food and as an additive in many culinary items.
  • Coconut shell is used for making many useful items, like a ladle, toys, etc.
  • Coconut leaf is used for making hand-fan, basket, mat, etc.
  • Veins of coconut leaf are used for making a broom.
  • Coconut fibre (coir) is used for making mattresses, carpets, ropes, etc.
  • Coconut wood is used in construction and furniture.
  • Coconut oil is used for various purposes all across the country.

Question:5

What are the basic characteristics of a modem landfill site? List any three and also mention the reasons for their use.

Answer:

Characteristic of a modern landfill site are as follows:
(a) Methods to contain leachates such as lining clay or plastic liners: This helps in preventing the leachate from seeping into the underground aquifers. This prevents soil population and groundwater pollution.
(b) Compaction and covering of the waste to prevent it from being blown by the wind: Compaction helps in better space utilization because more waste can be accommodated in a smaller area. Covering prevents the spread of dust and harmful germs and is thus safer from a health perspective.
(c) Installation of a landfill gas extraction system to extract the gas for use in the generation of power: This enables a faster generation of methane, which can be used for power generation. In some countries, landfill sites have become important contributors to power generation.

Question:6

How does an electrostatic precipitator work?

Answer:

An electrostatic precipitator is a device which is used to extract the suspended dust particles from the gas.
Working of an electrostatic precipitator is as follows:
  • High voltage charge is used to collect particles on the charged plates. Electrode wires, maintained at high voltages, produce a corona that releases electrons.
  • These electrons attach to dust particles and give them a net negative charge.
  • Grounded collecting plates attract negatively charged dust particles. Thus, dust particles are removed from the air. A spray of water or lime is generated in the scrubber and exhaust is passed through this spray. Scrubber removes gases, like Sulphur dioxide from the air. Thus, polluting gases like Sulphur dioxide are removed from the air.
  • Electrostatic precipitator can remove over 99% particulate matter present in the exhaust from a thermal power plant.

Question:7

Observe figure and answer the following questions. i. What ecological term is used to describe the DDT accumulation at different trophic levels?

i. What ecological term is used to describe the DDT accumulation at different trophic levels?

Answer:

(i) Biomagnification is the ecological term used to describe DDT accumulation at different trophic levels.
(ii) An effect of DDT accumulation on birds includes thinning of eggshells, and their premature breaking as the metabolism of birds get disturbed.
(iii) DDT accumulation leads to eutrophication, i.e. increased life in a water body.
(iv) DDT accumulation leads to eutrophication, which ultimately results in increased Biological Oxygen Demand.
(v) Minamata disease happens due to accumulation of mercury, Blackfoot due to arsenic and Itai- Itai due to cadmium.


Class 12 Biology NCERT exemplar solutions chapter 16 includes details on how sustainable development is being set up. Due to environmental issues posing a threat as our natural resources are rapidly depleting due to overpopulation at an uncontrollable speed to an extent where it could get extinct or be scarcely available for the future generations. Which is why sustainable development is so important.

NCERT Exemplar Class 12 Biology Solutions Chapter 16 Environmental Issues- Main Subtopics

  • Air Pollution and Its Control
  • Water Pollution and Its Control
  • Solid Wastes
  • Agro-chemicals and their Effects
  • Radioactive Wastes
  • Greenhouse Effect and Global Warming
  • Ozone Depletion in the Stratosphere
  • Degradation by Improper Resource Utilisation and Maintenance
  • Deforestation
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What will the students learn in NCERT Exemplar Class 12 Biology Solutions Chapter 16?

The year 2020 is the best example when environmental issues have manifested itself- be it the bush fire in Australia or the cyclone Nisarga. There's no one effect of it but innumerable conditions and causes. It is high time each one of us is aware of these causes and start taking preventive measures for the same. This chapter aims to instil the habit of environmental conservation among the students and make them conscious of the everlasting environmental issues. It wants the young generation to leave a better environment for future generations.

NCERT Exemplar Class 12 Biology Chapter Wise Links:

NCERT Exemplar Class 12 Biology Solutions Chapter 16 Environmental Issues- Important Topics

NCERT exemplar Class 12 Biology chapter 16 solution also explores causes of Environmental degradation such as different types of wastes, effects of agrochemicals, greenhouse effect causing environment issues such as global warming, depletion of the ozone layer, deforestation and forest fires. However, just a basic understanding of these concepts is not enough. Hence, the chapter further progresses to provide solutions to these problems, in turn, contributing to environmental conservation.

Before stepping into a detailed description of terms and concepts, let's have a brief understanding of it. What exactly does global warming mean? You might not know the accurate answer but must have experienced it. Have you felt unbearable heat even without summers? Have you noticed the blurry, cloudy skyline often known as smog?

That's exactly what global warming refers to. According to NCERT exemplar Class 12 Biology solutions chapter 16, Global warming is an increase in the average temperature of the surface of the earth. Another possible impact of global warming is a disturbance in the natural water cycle causing fluctuations in rain patterns leading to irregular or unseasonal rainfall.

Greenhouse gases include methane, carbon dioxide and water vapour that trap the solar rays and provide warmth to the earth. However, the increase in these gases results in global warming. Depletion of the ozone layer in the stratosphere is another issue of environmental degradation. The stratosphere is a layer of earth's atmosphere.

The obvious thought after reading this that would come to the mind is how we can prevent this? NCERT exemplar solution for Class 12 Biology chapter 16 also deals with 3R's being Reduce, Reuse and Recycle. The 3Rs come into the picture mainly when waste management is involved. Environmental Issue is a chapter that one needs to take extremely seriously not just from the academic point of view but also for preventing harm to nature.

NCERT Exemplar Class 12 Solutions Subject Wise:

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Frequently Asked Question (FAQs)

1. Is this chapter important for exams than other chapters?

Every chapter is important for the exams. Only their weightage differs giving them more or less importance compared to each other.

2. Who has prepared the NCERT exemplar solutions for Class 12 Biology chapter 16?

The NCERT exemplar Class 12 Biology chapter 16 solutions are prepared by us. We, professionals, prepare the solutions after carefully examining and referring to many advanced books.

3. Can I download the solutions for this chapter?

Yes, you can easily download this chapter by using the link provided on the page to get an NCERT exemplar Class 12 Biology solutions chapter 16 pdf download.

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The best method to draw notes from any chapter is to read it thoroughly and note down the important points in your own words. You can also draw diagrams or create patterns for better understanding.

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Questions related to CBSE Class 12th

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Yes, you can give improvement exams for 2-3 subjects in CBSE (Central Board of Secondary Education). CBSE allows students who have appeared for their Class 12 board exams to improve their scores by re-appearing for exams in up to five subjects the following year.


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Thank you

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  • Schools with ongoing admissions: Some schools, due to transfers or other reasons, might still have seats available even after the main admission rush.  Reach out to the schools directly to see if they have any open seats in 10th grade.

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In India, the design and coding fields offer exciting career options that can leverage your interest in both. Here's how you can navigate this path:

Choosing Your Stream:

  • Graphic Design Focus: Consider a Bachelor's degree in Graphic Design or a design diploma. Build a strong portfolio showcasing your creative skills. Learn the basics of HTML, CSS, and JavaScript to understand web development better. Many online resources and bootcamps offer these introductory courses.

  • Coding Focus: Pursue a Computer Science degree or a coding bootcamp in India. These programs are intensive but can equip you with strong coding skills quickly. While building your coding prowess, take online courses in graphic design principles and UI/UX design.

Engineering Subjects (for a Degree):

  • Information Technology (IT): This offers a good mix of web development, networking, and database management, all valuable for web design/development roles.

  • Human-Computer Interaction (HCI): This is a specialized field that bridges the gap between design and computer science, focusing on how users interact with technology. It's a perfect choice if you're interested in both aspects.

  • Passing NIOS in October 2024 will make you eligible for NIT admissions in 2025 . NIT admissions are based on your performance in entrance exams like JEE Main, which typically happen in January and April. These exams consider the previous year's Class 12th board results (or equivalent exams like NIOS).

Here's why 2025 is more likely:

  • JEE Main 2024 Admissions: The application process for NITs through JEE Main 2024 is likely complete by now (May 2024). They consider your 2023 Class 12th marks (CBSE in this case).
  • NIOS Results: Since NIOS results typically come out after the NIT admission process, your October 2024 NIOS marks wouldn't be available for JEE Main 2024.

Looking Ahead (2025 Admissions):

  • Focus on JEE Main: Since you have a computer science background, focus on preparing for JEE Main 2025. This exam tests your knowledge in Physics, Chemistry, and Mathematics, crucial for engineering programs at NITs.
  • NIOS Preparation: Utilize the time between now and October 2024 to prepare for your NIOS exams.
  • Eligibility Criteria: Remember, NITs typically require a minimum of 75% marks in Class 12th (or equivalent) for general category students (65% for SC/ST). Ensure you meet this criteria in your NIOS exams.

Yes, scoring above 99.9 percentile in CAT significantly increases your chances of getting a call from IIM Bangalore,  with your academic background. Here's why:

  • High CAT Score: A score exceeding  99.9 percentile is exceptional and puts you amongst the top candidates vying for admission. IIM Bangalore prioritizes  CAT scores heavily in the shortlisting process.

  • Strong Academics: Your 96% in CBSE 12th and a B.Tech degree demonstrate a solid academic foundation, which IIM Bangalore also considers during shortlisting.

However, the shortlisting process is multifaceted:

  • Other Factors: IIM Bangalore considers other factors beyond CAT scores, such as your work experience (if any), XAT score (if you appear for it), academic diversity, gender diversity, and performance in the interview and Written Ability Test (WAT) stages (if shortlisted).

Here's what you can do to strengthen your application:

  • Focus on WAT and PI: If you receive a shortlist, prepare extensively for the Written Ability Test (WAT) and Personal Interview (PI). These stages assess your communication, soft skills, leadership potential, and suitability for the program.

  • Work Experience (if applicable): If you have work experience, highlight your achievements and how they align with your chosen IIM Bangalore program.

Overall, with a stellar CAT score and a strong academic background, you have a very good chance of getting a call from IIM Bangalore. But remember to prepare comprehensively for the other stages of the selection process.

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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)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

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)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} 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

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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