Bihar Board Class 9 English Book Solutions Chapter 3 A Silent Revolution
A. Work in small groups and discuss the relationship between population and pollution.
You may include these points in your discussion:
Its effect on the development of the country
More people, more land
Answer:
Nowadays, environmental pollution has increased rapidly due to population explosion. This problem is a serious concern for both society and the government. Overpopulation has become a major obstacle to the development of the country. As the population increases, human activities such as industrial growth, urbanisation, and deforestation also increase. People cut down forests to build houses, factories, and farmlands. More people require more land for living and cultivation. Deforestation causes air pollution and soil erosion because trees protect the soil. When trees are cut down, the fertile topsoil is washed away, creating further environmental problems.
B.1.1. Write ‘T’ for true and ‘F’ for false statements:
Throughout most of human existence, the number of births was slightly higher than the number of deaths.
More people will need even less food than they need now.
With more people, both town and country become more crowded.
Higher population density is also not likely to exacerbate crime, ethnic conflict and warfare.
Population size and rates of growth are key elements in environmental change.
Answer:
– T
– F
– T
– F
– T
B.1.2. Answer the following questions very briefly:
Question 1.
For how long has the global population been rapidly going up?
Answer:
The global population has been rapidly increasing for the last three centuries.
Question 2.
What happens when the population goes up?
Answer:
When the population increases, pollution of rivers, lakes, air, drinking water, and soil also increases. As a result, the quality and value of life continue to decline.
Question 3.
How many Americans die each day of asthma?
Answer:
Fourteen Americans die each day due to asthma aggravated by air pollution.
B.2.1. Complete the following sentences on the basis of the lesson:
The more we have, the better __________
History and common sense tell us that we _________
As the population grows, more and more people are forced _________
Forest covered around 40% of the earth’s __________
Humanity can continue to fell trees, cross its finger, and ___________
Answer:
off we are.
can control population growth.
to convert forests into farmlands.
total land area.
hope for the best.
B.2.2. Answer the following questions very briefly:
Question 1.
Name the countries in which the population growth has been slowed down remarkably?
Answer:
In countries such as China, Thailand, and Egypt, the rate of population growth has slowed down remarkably.
Question 2.
The productivity and general health of the world’s forest are threatened. How?
Answer:
The productivity and health of the world’s forests are threatened by the greenhouse effect, depletion of the ozone layer, airborne pollution, and acid rain.
Question 3.
What hampers the ability of the biosphere to sustain life?
Answer:
Deforestation reduces the quality of life on Earth and decreases the number of living species. This damage hampers the ability of the biosphere to sustain life.
Question 4.
How does deforestation in Nepal affect India?
Answer:
Deforestation in Nepal leads to loss of topsoil, and heavy rainfall then causes floods. These floods often flow into India, causing severe damage.
C. Long Answer Type Questions
Question 1.
Why have human populations always been in flux?
Answer:
Human populations have always been in flux because births and deaths occur every day. However, a few hundred years ago, especially in industrialised countries, the situation changed. Due to improvements in nutrition, sanitation, and healthcare, people began to live longer. As more people reached reproductive age, the population started increasing rapidly.
Question 2.
What does the writer mean by reproductive age? How do people reach this age?
Answer:
By reproductive age, the writer means the age at which people are biologically capable of producing children. This age generally begins around 15 years and continues up to about 50 years. Due to better nutrition, sanitation, and healthcare, people now live longer and remain healthy enough to reach and remain in reproductive age.
Question 3.
What is human-made pollution? How has it affected America? How will it affect your locality?
Answer:
Human-made pollution is caused by activities such as deforestation, depletion of non-renewable resources, ozone layer depletion, and the greenhouse effect. These forms of pollution have badly affected America. According to estimates, about 60,000 Americans die every year due to respiratory diseases caused by pollution. Our locality is also affected by human-made pollution. Garbage is thrown openly, drainage systems are poor, and air quality is declining. This creates serious health problems and spreads diseases.
Question 4.
Population size and rates of growth are a key element in environmental change. Explain with any two examples from your own society.
Answer:
Population size and growth rate play a major role in environmental change. As the population increases, more food and housing are needed, which leads to deforestation. In my village, a family cut down its orchard to build new houses, making the area barren. Another example is my locality in Patna, where farmlands have been replaced by roads and houses. What was once an agricultural area has now become a crowded housing colony.
Question 5.
How do countries like Germany, Switzerland, China, Thailand and Egypt manage to ‘reverse’ or slow down population growth? What does ‘reverse’ mean here? How has it been possible?
Answer:
These countries have managed to reverse or slow down population growth. Here, ‘reverse’ means reducing the rate of population increase. This has been possible due to factors such as modernisation, increased literacy, media awareness campaigns, availability of family planning methods, contraceptives, and equal economic, educational, and legal opportunities for women.