EXERCISE

Q1. Write in your own words the meaning of environment.
Answer: The environment is the surroundings in which living things exist. It includes both living (biotic) things like plants and animals, and non-living (abiotic) things like land, water, and air. The environment is formed by the interaction of the lithosphere, hydrosphere, atmosphere, and biosphere.

Q2. Mention some of the biotic and abiotic elements of environment.
Answer: The elements of the environment are broadly classified into biotic and abiotic categories. Biotic elements include all living things, such as plants and animals, ranging from tiny microbes to large mammals, while abiotic elements consist of non-living components like land, water, and air, which provide the essential conditions for life to exist and interact within an ecosystem.

Q3. Write the meaning of lithosphere.
Answer: The lithosphere is the land component of the Earth’s environment. It is composed of rocks, soils, and minerals. It covers all the continents and includes landforms such as mountains, hills, plateaus, plains, valleys, and coasts.

Q4. What are the features included in the hydrosphere?
Answer: The hydrosphere includes all the water components of the Earth. This covers the seas and oceans, which make up about 71% of the Earth’s surface. It also includes other water bodies found on the continents, such as rivers and lakes.

Q5. Write about the composition of the atmosphere.
Answer: The atmosphere is a gaseous layer that extends from the Earth’s surface. Its main components are Oxygen, Nitrogen, Hydrogen, Carbon-di-Oxide, and Argon. The atmosphere extends to a height of about 10,000 km from the Earth’s surface.

Q6. Give an outline of the extent of the biosphere.
Answer: The biosphere is the part of the Earth’s environment where life exists. It extends from a few meters down into the Earth’s surface, through the seas and oceans, and up to the lower layer of the atmosphere where birds and insects fly. So far, about 1.75 million species of plants and animals have been identified in the biosphere, including human beings.

Q7. Discuss briefly the relation among the four major components of environment.
Answer: The four major components of the Earth’s environment—the lithosphere, hydrosphere, atmosphere, and biosphere—are all interconnected and interdependent. The interactions among them are what create the environment. For example, the status of the hydrosphere (water) is dependent on the status of the other three components. Similarly, the characteristics of the atmosphere depend on the other components of the environmental system. Changes in one sphere can cause changes in the others, as seen with deforestation, which can negatively impact the biosphere and atmosphere. The earth’s environment is a vast and complicated system where all elements are in a complicated network of relationships.

Q8. Mention the major causes of environmental change.
Answer: The major causes of environmental change are:

1. Human activities such as population growth, industrialization, and urbanization.
2. Expansion of transport and communication systems affecting natural habitats.
3. Decline in forest cover and wetlands, reducing ecological balance.
4. Natural disasters like volcanic eruptions and forest fires.
5. Pollution added to the atmosphere from both human and natural sources.

Q9. Explain the meaning of environmental problem.
Answer: An environmental problem occurs when the quality of natural resources or the balance between living and non-living things is disturbed. In the past, people lived with natural events like earthquakes and volcanic eruptions. But with the growing population and increased use of resources, this balance is disrupted, leading to problems like pollution and global warming, which are called environmental problems.

Q10. Write geographical divisions of the environmental problems.
Answer: Environmental problems can be divided into three groups:

1. Local problems: Confined to small areas. Examples: land pollution from a small industry, water shortage in a wetland, or riverbank erosion in one locality.
2. Regional problems: Affect a larger area. Examples: floods in the Brahmaputra or Barak Valley, water pollution in industrial regions, or soil erosion in a river basin.
3. Global problems: Affect the whole world without boundaries. Example: global warming, impacting the atmosphere, land, water, and living things everywhere.

Q11. What is a local environmental problem? Give examples.
Answer: A local environmental problem is an issue that occurs in a small area and affects only that place. These problems can usually be solved by the local community or authorities. Examples include land pollution from a small industry, water shortage in a village due to a shallow wetland, and riverbank erosion in a specific locality.

Q12. Give two examples of regional environmental problem.
Answer: Two examples of regional environmental problems are:

1. The flood problem of the Brahmaputra or the Barak Valley: This is a recurring issue that affects a large area and multiple communities within a specific geographical region.
2. The problem of water pollution in a vast industrial region: This issue extends beyond a single factory or town, contaminating the water bodies across a significant industrial area.

Q13. Which problems are considered as global environmental problem?
Answer: Global environmental problems are those that affect the entire world and transcend geographical boundaries. Their impact is felt across different continents and environmental spheres—the lithosphere, hydrosphere, and biosphere—in addition to the atmosphere. The management of these problems requires international cooperation and effort. The most prominent example of a global environmental problem is global warming.

Q14. Mention the major environmental problems of the world.
Answer: The major environmental problems caused by human activities are:

1. Pollution: Harmful substances contaminate land, air, and water, affecting humans, animals, and plants.
2. Desertification: Fertile land in tropical areas becomes like a desert due to overuse, deforestation, and natural factors.
3. Global Warming: The Earth’s temperature rises because of more greenhouse gases, leading to climate change.
4. Landslides and soil erosion: Soil and rocks are washed away from hills and mountains, causing loss of fertile land and damage to settlements.
5. Artificial floods and rising sea levels: Human activities like dam construction, deforestation, and global warming increase flood risks and cause sea levels to rise, threatening coastal areas.

Q15. Give the meaning of the term pollution.
Answer: Pollution is the contamination of the environment with harmful substances called pollutants. When these substances enter land, water, or air in large amounts, they can harm humans, animals, plants, and the overall ecosystem.

Q16. What is water pollution? How does it occur?
Answer: Water pollution happens when water is contaminated by chemicals, particles, microbes, or radiation, making it harmful for humans and aquatic life.

It occurs in several ways:

1. Industrial and urban wastes: Factories and towns release waste into rivers. For example, the Ganga river and the Bharalu river in Guwahati are polluted by industrial and urban waste.
2. Agricultural factors: Fertilizers and pesticides used in farming can pollute water. In the U.S., 55% of rivers are polluted due to agriculture.
3. Acid rain: Sulphur dioxide and nitrogen oxide in the air fall as acid rain, polluting water and harming aquatic life.
4. Ocean pollution: Oceans are polluted by industrial waste and oil spills from ships.

Q17. Write a short note on land pollution.

Answer: Land pollution occurs when land loses its natural properties and fertility due to contact with harmful substances like chemicals, poisonous metals, industrial wastes, and radioactive materials. This process is largely driven by human activities.

Modern farming practices are a major cause, as the extensive use of chemical fertilizers, insecticides, and weedicides alters soil composition, harms beneficial microbes, and pollutes the land. Industrial activities also contribute significantly, as industrial wastes and chemical substances mix with the soil. In addition, improper extraction of coal and petroleum can pollute the land. As a result of these factors, land pollution has become a widespread problem in many parts of the world.

Q18. Write how air is polluted.
Answer: Air pollution occurs when harmful solid, liquid, or gaseous substances disturb the natural balance of air. It can be caused by natural factors like volcanic eruptions, which release smoke, ash, and gases such as sulphur dioxide, and forest fires that add smoke and harmful particles.

Human activities also contribute to air pollution. Industrial emissions release gases like carbon monoxide, nitrogen oxide, and sulphur dioxide, while urbanization and vehicle traffic increase harmful gases in the atmosphere. Nuclear explosions also release dangerous radiations. One major effect of air pollution is acid rain, which can destroy forests and pollute water bodies.

Q19. What is a desert? Give the definition of desertification.
Answer: A desert is a naturally dry region with very little rainfall and high evaporation, resulting in sparse vegetation. About 20% of the world’s land surface is covered by deserts, including cold deserts in polar regions.

Desertification is the process by which fertile land in tropical regions becomes desert-like. It is defined as the loss of the land’s biological potential, leading to desert conditions. Desertification also includes the spread of existing deserts into nearby areas, reducing land productivity. Currently, about 35% of the world’s land is affected by this process.

Q20. Mention the causes of desertification.
Answer: The causes of desertification include:

1. Drought: Long periods without rain reduce land productivity and vegetation growth.
2. Global warming: Rising temperatures make dry areas even drier.
3. Overgrazing: Too much grazing by livestock removes vegetation, causing soil erosion.
4. Expansion of agriculture: Poor farming practices deplete soil nutrients and degrade the land.
5. Deforestation: Cutting down trees exposes soil to erosion and moisture loss.
6. Rapid population growth: Increased human activities put pressure on land, helping deserts to expand.

Q21. Is it possible to control desertification?
Answer: Yes, it is possible to control desertification, but it is a challenging task that requires international cooperation. The problem is gradually becoming more complicated because of its link with processes like global warming. To resist desertification, it is important to take steps to reduce human activities that are harmful to nature. This includes preventing overgrazing, controlling deforestation, and adopting sustainable land-use practices.

Q22. What is global warming? Mention its causes.
Answer: Global warming is the rise in the average temperature of the Earth’s atmosphere and surface, which has become a major threat to life on Earth.

The main cause of global warming is the increase in greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and chlorofluorocarbons (CFCs), which trap heat in the atmosphere.

Causes of greenhouse gas increase include:

1. Human activities: Burning fossil fuels in industries and vehicles, and deforestation, which reduces the number of trees that absorb CO₂.
2. Natural factors: Volcanic eruptions that release greenhouse gases into the atmosphere.
3. As a result, the Earth’s average surface temperature has risen by about 0.76°C since the pre-industrial period.

Q23. What are the probable consequences of global warming?
Answer: The rise in Earth’s temperature due to global warming can cause serious problems that threaten life on Earth. The probable consequences include:

1. Melting of polar ice: A 2–3°C rise in temperature could melt ice and snow in polar regions.
2. Rise in sea level: Melting ice can raise sea levels, potentially submerging about 5 million sq. km of coastal areas and many islands and deltas.
3. Impact on biodiversity: Changes in temperature can affect the growth and distribution of plants and animals, threatening species.
4. Agricultural decline: Crop production may fall, causing food shortages.
5. Desertification: Global warming can make dry areas even drier, increasing desertification.

Q24. Write how to control global warming.
Answer: To control global warming, people and countries must work together to reduce greenhouse gases in the atmosphere. Key steps include:

1. Reducing fossil fuel use: Use renewable energy sources like solar, wind, and hydroelectric power instead of coal and petroleum.
2. Promoting energy efficiency: Use technologies and practices that save energy.
3. Afforestation and reforestation: Plant more trees and protect forests, as trees absorb carbon dioxide.
4. International cooperation: Countries should work together and follow global plans guided by organizations like the United Nations to limit temperature rise.

Q25. Is there any environmental problem in your own locality? If yes, then explain their causes and indicate some measures for their solution.
Answer: Yes, there are environmental problems in my locality, which is a small town near a river. One major problem is water pollution, as the river has become dirty and unsafe for domestic use or fishing. The main causes are urban waste, where municipal sewage and garbage are dumped directly into the river; industrial waste from small workshops and garages; and a lack of awareness, with people throwing trash into the river without knowing the consequences.

Measures to solve this problem include proper waste management with garbage collection and sewage treatment, public awareness campaigns to educate people about clean water, strict enforcement of laws to prevent illegal dumping, and community involvement through clean-up drives and monitoring the river’s health.