Biology

NIOS Class 12 Biology Chapter 27 Terminal Exercises

NIOS Biology Chapter 27 Pollution Solutions provides answers to terminal exercises and explains causes, effects, and control of pollution. Students study air, water, soil, and noise pollution along with preventive measures. This chapter builds awareness about environmental issues.

Solved solutions make revision simple and exam-oriented. It is an important chapter for both academic preparation and real-world understanding, making it a key part of the NIOS Class 12 Biology curriculum.

NIOS Biology Chapter 27 Pollution Solutions

1. Which of the following are biodegradable materials?

Aluminium, wood, fruit peels, DDT, paper, glass, dung

Wood, fruit peels, paper, and dung.

2. Which gaseous pollutant can absorb infrared radiation?

Carbon dioxide and methane are gaseous pollutants that can absorb infrared radiation.

3. A ship carrying oil from the Gulf region collides with huge rocks and is damaged. Is this just news, or does it have some serious consequences? Give your opinion in one sentence.

The ship carried oil, which was spilled and polluted the ocean water. Such pollution can cause the death of aquatic plants and animals.

4. To set up a new industry, a large forest area had to be cut down. List four ways in which the environment in that area may be affected.

Extensive cutting down of forests and trees exposes the ground surface to the direct impact of rain and wind. For example, in the absence of proper vegetation cover, there is no interception of rainfall, and the falling rain strikes the soil surface directly, resulting in the throwing up of loose soil particles in the air, which are washed away by rainwater.
The factory could cause air pollution that can lead to health problems in the public or increase the chances of emitting greenhouse gases.
It may change the local climate over the period.
Chances of water pollution from the waste expelled due to the industry.
Noise from the industry is another threat in the area.

5. List any three ways in which noise from various sources can affect the well-being of a person. Suggest a few methods to control noise pollution.

Effects of noise pollution

Inability to sleep, slow recovery from sickness.
Irritability and interference in communication.
Temporary loss of hearing, earache, and sometimes even leading to permanent deafness.
Inability to concentrate, headache.
Ringing of ears (a feeling, sound coming from within the ear in a very quiet environment).
Increased blood pressure, irregular heartbeat.

The following steps can be taken to control or minimize noise pollution:

Control the noise emanating from your radio and television.
Use automobile horns only in case of emergency.
Do not burn firecrackers as they are noisy and also cause air pollution.
Get all machinery and engines properly tuned and serviced at regular intervals and by the use of silencers.
Use of soundproof cabins and sound-absorbing materials in the walls.
A green belt of vegetation is an efficient absorber of noise.
Not playing loudspeakers during odd hours. It is legally banned and should be reported to the police immediately.

6. What does ‘Global warming’ mean? Name the gas responsible for this phenomenon, and why should it be considered an environmental problem?

Global warming is the rise in atmospheric temperature due to the greenhouse effect. Carbon dioxide, chlorofluorocarbons, etc, are some of the main gases responsible for this phenomenon.

The increased surface temperature would cause melting of continental and mountain glaciers and thus would cause flooding of coastal areas of some countries.
Global warming will produce severe heat waves during the summer, causing heat-related illness and death.
Due to the increased temperature of Earth’s atmosphere, the precipitation of water will increase. This will decrease the soil moisture content and lead to frequent downpours, also.

7. How would you classify the waste generated at home? What is the difference between the different groups? How would you manage this waste so that it causes the least pollution?

Waste generated at home can be categorised into biodegradable and non-biodegradable. The latter can be further classified into recyclable materials.

The biodegradable waste includes kitchen waste, dung, etc. They may be used to make compost to reduce their accumulation in the landfill.
Kitchen waste might also be used to generate biogas, which can be used as cooking gas.
The non-biodegradable waste includes plastic, glass, and other materials that may be recycled.