NCERT Exemplar solutions for Biology [English] Class 12 chapter 16 - Environmental Issues [Latest edition]

Non-biodegradable pollutants are created by ______.

According to the Central Pollution Control Board, the diameter of particles that are responsible for causing great harm to human health is ______.

The material generally used for sound proofing of rooms like a recording studio and auditorium is ______.

Compressed Natural Gas (CNG) is ______.

World’s most problematic aquatic weed is ______.

Which of the following exhibits biomagnification?

The expanded form of DDT is ______.

Which of the following material takes the longest time for biodegradation?

Choose the incorrect statement.

Among the following which one causes maximum indoor chemical pollution?

The green scum seen in the fresh water bodies is ______.

The loudness of a sound that a person can withstand without discomfort is about ______.

The major source of noise pollution world wide is due to ______.

Match the following and choose the correct option:

The correct matches are:

Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unburnt hydrocarbons into ______.

Why is it necessary to remove sulphur from petroleum products?

Which one of the following impurities is easiest to remove from wastewater?

Which one of the following diseases is not caused due to contamination of water?

Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentrations of ______.

Algal blooms impart a distinct colour to water due to ______.

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

The correct match is:

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?

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

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

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

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?

What is cultural eutrophication?

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

What is the raw material for polyblend?

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

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

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

What is an algal bloom?

What do you understand by biomagnification?

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

What is reforestation?

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

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

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

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.

Name any one green house gas and its possible source of production on a large scale. What are the harmful effects of it?

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

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

How can slash and burn agriculture become environment friendly?

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

What do you understand by Snow-blindness?

How has DDT caused decline in bird population?

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

A	B

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

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

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

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

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

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

How does an electrostatic precipitator work?

Observe figure and answer the following questions.

Biomagnification of DDT in an aquatic food chain

1. What ecological term is used to describe the DDT accumulation at different trophic levels?
2. List any one effect of DDT accumulation on birds
3. Will DDT accumulation lead to eutrophication?
4. Does it affect the BOD?
5. Name disease caused by accumulation of any heavy metal.