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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
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) humansQuestion: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 micrometersQuestion: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) StyrofoamQuestion:4
Compressed Natural Gas (CNG) is:
a. propane
b. methane
c. ethane
d. butane
Answer:
The answer is the option (b) methaneQuestion:5
World’s most problematic aquatic weed is:
a. Azolla
b. Wolffia
c. Eichhornia
d. Trapa
Answer:
The answer is the option (c) EichhorniaQuestion: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)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 trichloroethaneQuestion: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) BoneQuestion: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 contentQuestion: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 coalQuestion: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 systemQuestion:14
Match the following and choose the correct option
Column I | Column II |
A. Environment Protection Act | i. 1974 |
B. Air Prevention & Control of Pollution Act | ii. 1987 |
C. Water Act | iii. 1986 |
D. Amendment of Air Act to include noise as an air pollutant | iv. 1981 |
Answer:
The answer is the option (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 waterQuestion: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 fumesQuestion: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 solidsQuestion: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-BQuestion: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) phosphorusQuestion: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 pigmentsQuestion:21
Match the items in column I and column II and choose the correct option:
Column I | Column II |
A. UV | i. Biomagnification |
B. Biodegradable Organic matter | ii. Eutrophication |
C. DDT | iii. Snow blindness |
D. Phosphates | iv. BOD |
Answer:
The answer is the option (c) A (iii), B (iv), C (i), D (ii)Question:22
In the textbook, you came across ''Three Mile Island and Chernobyl disasters associated with accidental leakage of radioactive wastes''. In India we had Bhopal gas tragedy. It is associated with which of the following?
a. CO2
b. Methyl Isocyanate
c. CFC
d. Methyl Cyanate
Answer:
The answer is the option (b) Methyl Iso-CyanateQuestion:1
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
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
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: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
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
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.Question:14
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.Question:1
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.Question:3
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
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
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
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
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.Question:1
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.Question:2
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.Question:3
Answer:
Waterlogging and soil salinity are some of the problems that have come in the wake of the green revolution.Question:4
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:Question:5
Answer:
Characteristic of a modern landfill site are as follows: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.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.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.
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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 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.
Chapter 1 | |
Chapter 2 | |
Chapter 3 | |
Chapter 4 | |
Chapter 5 | |
Chapter 6 | |
Chapter 7 | |
Chapter 8 | |
Chapter 9 | |
Chapter 10 | |
Chapter 11 | |
Chapter 12 | |
Chapter 13 | |
Chapter 14 | |
Chapter 15 | |
Chapter 16 |
Every chapter is important for the exams. Only their weightage differs giving them more or less importance compared to each other.
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.
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.
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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Ah, you're looking for CBSE quarterly question papers for mathematics, right? Those can be super helpful for exam prep.
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If you're after more practice material, some textbook publishers release their own mock papers which can be useful too.
Let me know if you need any other tips for your math prep. Good luck with your studies!
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hello mahima,
If you have uploaded screenshot of your 12th board result taken from CBSE official website,there won,t be a problem with that.If the screenshot that you have uploaded is clear and legible. It should display your name, roll number, marks obtained, and any other relevant details in a readable forma.ALSO, the screenshot clearly show it is from the official CBSE results portal.
hope this helps.
Hello Akash,
If you are looking for important questions of class 12th then I would like to suggest you to go with previous year questions of that particular board. You can go with last 5-10 years of PYQs so and after going through all the questions you will have a clear idea about the type and level of questions that are being asked and it will help you to boost your class 12th board preparation.
You can get the Previous Year Questions (PYQs) on the official website of the respective board.
I hope this answer helps you. If you have more queries then feel free to share your questions with us we will be happy to assist you.
Thank you and wishing you all the best for your bright future.
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