Our World Today
(Longman Pearson)
Review Exercise
I. Fill in the blanks.
1. The Industrial Revolution marked the beginning of technological advancement and scientific progress.
2. Rainfall that contains harmful substance such as chemicals is called acid rain.
3. The greenhouse effect had led to uneven increase in temperatures which is referred to as global warming.
4. The greenhouse effect had caused large holes in the Earth's protective ozone layer.
5. Radioactive leaks usually occur from nuclear power plants.
6. Any sound that is disturbing or unpleasant is termed as noise.
7. Noise Regulation Rules were passed by the government of India in 2000.
8. The unfiltered Ultra Violet (UV) rays from the Sun has exposed people to the risk of skin cancer.
9. Large-scale depletion of forests had caused soil erosion and destroyed the natural habitat of birds and animals.
II. Answer these questions.
1. What is pollution? State different types of pollution.
= Pollution in the environment is a very serious problem which hampers the health of the people around the globe. Pollution is found on land, in air and water.
2. List at least three sources of noise pollution. What are the harmful effects of noise pollution on humans?
= Three sources of noise pollution are - sound of traffic, heavy machines and loud speakers.
Noise Pollution can lead to mental and physical ailments. They can cause permanent or partial deafness, anger, tension or lack of concentration.
3. State the factors that cause pollution.
= Pollution is caused by several factors :
❐ Overpopulation.
❐ Throwing industrial toxic wastes into water bodies.
❐ Deforestation.
❐ Use of chemical pesticides and fertilisers.
❐ Vehicles emitting harmful gases into the air.
❐ depletion of natural resources due to their overuse.
4. Water is precious natural resource and we must conserve it. Mention a few ways in which you can save water in your day-to-day life.
= Water is precious natural resource and we must conserve it. A few ways in which we can save water in our day-to-day life are :
❐ Take quick shower.
❐ Check leaks on water pipes and in toilets.
❐ Stop the nob of the tap while brushing.
❐ Turn of the nob of the tap while shaving.
❐ After washing the clothes, the water should be used to water the plants.
5. What is noise pollution?
= Any sound that is disturbing or unpleasant is termed as noise. Noise pollution can caused by the sound of traffic, heavy machines and loud speakers. These sounds can lead to mental and physical ailments.
6. What is air pollution? State the cause of air pollution.
= Air pollution is chiefly caused by smoke from factories and fumes from vehicles. Rapid industrialisation that began during the World War years also gave rise to urbanisation.
The main focus of the industries was to make profits and little attention was paid to the side effects on the environment.
7. How has overpopulation affected the Earth's environment?
= Overpopulation is an important factor that has caused environment degradation. The rising population and their demands have led to rapid depletion of the world's natural resources. Our Earth has limited resources and it will not be able to sustain the growing population. If population growth is not checked, it may lead to starvation and worse living conditions.
8. List the various causes of water pollution.
= The ware in rivers, seas and lakes are polluted by the waste products that are disposed of in them :
❐ Oil spills in oceans contaminate water and kill thousands of sea animals and birds.
❐ The toxic waste from heavy industries is dumped in water bodies, particularly rivers, which are a source of fresh water.
❐ The harmful fertilisers use by farmers are drained into water bodies by rain. This adds chemicals to water bodies.
❐ Water pollution is also caused by idol immersion, bathing cattle and washing clothes and utensils in fresh water sources.
9. The use of chemical fertilisers and pesticides cause pollution. Explain.
= Chemical fertilisers and pesticides cause soil and water.
The harmful fertilisers used by farmers are drained into water bodies by rain. This adds chemicals to water bodies.
Overuse of chemical fertilisers and pesticides damage the quality of soil.
10. Rapid industrialisation has been achieved at the cost of exploitation of natural resources. Do you agree? Justify your answer.
= I totally agree on the fact that rapid industrialisation has been achieved at the cost of exploitation of natural resources. Most of the natural resources of the Earth have been exhausted or are on the verge of being wiped out.
❐ Fossil fuels, which include coal, oil and gas, are being used at a rapid pace. A time will come when these resources will not be available any more.
❐ Metal resources such as tin, iron ore, copper and lead are being mined extensively. These metal resources, like fossil fuels, cannot be replaced.
❐ Forests are the most important source of timber. Depletion of forests has not only affected availability of timber but also animals and birds who have lost their natural habitat.
11. What are the harmful effects of air pollution?
= Polluted air cause health issues and breathing problems in animals and human beings. The harmful air, discharged from industries, caused a lot of damage to forest through acid rain.
12. Explain the term 'greenhouse effect'. How is it harmful?
= Air pollution causes greenhouse effect. The harmful air acts as the glass roof of a greenhouse. This layer of air in the atmosphere traps the heat of the Sun and cause uneven increase in temperatures or global warming. The greenhouse effect has led to serious consequences.
❐ Melting of glaciers, polar ice caps and snow on the mountains have raised the sea level and caused flooding of various regions.
❐ It has led to extremely high temperatures in many parts of Asia and Africa.
❐ Large holes in the Earth's protective ozone layer have been discovered by scientists. The unfiltered ultraviolet rays (UV rays) from the Sun reach the Earth's surface through these holes. These rays can cause skin cancer.
III. State whether true or false.
1. Overpopulation is a major factor that had caused depletion of our natural environment. [T]
2. Noise pollution can cause partial deafness and loss of concentration. [T]
3. Mineral resources are available in plenty on the Earth. [F]
4. Oil spills are harmful for marine life. [T]
5. The greenhouse effect has led to global cooling of our environment. [F]
IV. Write short notes.
1. Greenhouse effect.
= Air pollution causes greenhouse effect. The harmful air acts as the glass roof of a greenhouse. This layer of air in the atmosphere traps the heat of the Sun and cause uneven increase in temperatures or global warming. The greenhouse effect has led to serious consequences.
❐ Melting of glaciers, polar ice caps and snow on the mountains have raised the sea level and caused flooding of various regions.
❐ It has led to extremely high temperatures in many parts of Asia and Africa.
❐ Large holes in the Earth's protective ozone layer have been discovered by scientists. The unfiltered ultraviolet rays (UV rays) from the Sun reach the Earth's surface through these holes. These rays can cause skin cancer.
2. Causes of soil pollution.
= Excessive use of chemicals, fertilisers and pesticides causes land pollution. Garbage, rotten food and plastic waste add to land pollution.
❐ Overuse of chemical fertilisers and pesticides damage the quality of soil.
❐ Large-scale deforestation has led to soil erosion and destroyed the natural habitat of birds and animals. Due to lack of forest cover many species of animals have become extinct.
3. Conservation of environment.
= Several measures have been undertaken at the state, national and international levels to protect our environment. Some of the measures introduced in India are these :
❐ Use of compressed natural gas (CNG) in vehicles.
❐ Use of plastic bags is discouraged.
❐ Diesel vehicles which are more than ten years old have been banned in Delhi.
❐ Use of natural gas for cooking food is being encouraged. Natural gas is one of the cleanest burning fossil fuels and thus, environment friendly.
The loss of natural resources has damaged the ecosystem. We must learn to conserve our natural resources in order to save it for our future generations. Our environment is our life support system and it is our responsibility to protect it.