Unit Test( Solutions): Environment | Social Studies (SST) Class 7 (Old NCERT) PDF Download

Time: 1 hour
Maximum Marks: 30
Attempt all questions.
Question numbers 1 to 5 carry 1 mark each.
Question numbers 6 to 8 carry 2 marks each.
Question numbers 9 to 11 carry 3 marks each.
Question numbers 12 & 13 carry 5 marks each.

Q1: Fill in the blank: The solid crust or the hard top layer of the earth is called __________. (1 Mark)

Ans: Lithosphere

Q2: Which of the following is not a natural ecosystem? (1 Mark)
(a) Desert
(b) Aquarium
(c) Forest
(d) Grassland

Ans: (b) 
Aquarium

Q3: Match the following:

Ans:

Atmosphere - (b) Blanket of air which surrounds the earth

Hydrosphere - (c) Domain of water

Environment - (d) Our surroundings

Biosphere - (a) Narrow zone where land, water, and air interact

Q4: True or False: The lithosphere provides us land for agriculture, human settlements, and is a source of mineral wealth. (1 Mark)

Ans: True

Q5: Odd One Out: Buildings, Rivers, Bridges and  Roads (1 Mark)
Ans: River
 Rivers is not a man made component. 

Q6: Describe the natural environment and provide examples of its components. (2 Marks)

Ans: The natural environment includes the biotic and abiotic conditions existing on the earth. The biotic components are the living organisms like plants, animals, and microorganisms, while the abiotic components include non-living elements like land, water, air, and minerals.Examples of components:

Lithosphere – The land or solid crust of the Earth.

Hydrosphere – The domain of water, including rivers, lakes, seas, and oceans.

Q7: How do human beings modify the natural environment? (2 Marks)

Ans: Human beings modify the natural environment by their activities such as:

• Building structures like roads, bridges, and houses, which replace natural features.
• Deforestation for agriculture and urbanization, leading to habitat destruction.
• Industrialization, which causes pollution of air, water, and land.
• Use of natural resources, like mining for minerals, depletes the earth’s wealth.
• Agriculture, where natural landscapes are converted into fields for growing crops.

Q8 : Why is the biosphere important for living organisms? (2 Marks)

Ans:

• The biosphere is the narrow zone of the Earth where land, water, and air interact to support life.
• It provides the essential elements like air (oxygen), water, and nutrients, which are necessary for the survival of all living organisms.
• The biosphere includes ecosystems where plants, animals, and microorganisms coexist and depend on each other for food, shelter, and survival.
• The balance of life within the biosphere is vital for maintaining environmental stability and biodiversity.

Q9: Explain how man modifies his environment and the consequences of such actions. (3 Marks)

Ans:

• Construction of buildings and roads transforms the natural landscape, removing forests and grasslands.
• Industrialization leads to pollution of air, water, and land, affecting the health of ecosystems.
• Deforestation causes habitat destruction, leading to the extinction of species and loss of biodiversity.
• Over-exploitation of resources such as mining depletes the Earth's natural wealth and damages the environment.
• Urbanization creates large cities that put pressure on natural resources like water and energy.
• These modifications often lead to environmental problems like climate change, desertification, and water scarcity.

Q10: Describe how plants and animals depend on each other in an ecosystem. (3 Marks)

Ans:

• Plants produce oxygen during photosynthesis, which animals need for respiration.
• Animals provide carbon dioxide, which plants use for photosynthesis.
• Herbivores depend on plants for food, and carnivores depend on herbivores, forming a food chain.
• Animals like bees and butterflies help in the pollination of plants, allowing them to reproduce.
• Some animals help with seed dispersal, spreading plants to new areas.
• Decomposers like bacteria and fungi break down dead plants and animals, returning nutrients to the soil.

Q11: List and explain the major components of the environment. (3 Marks)

Ans:

• Lithosphere: The solid outer layer of the Earth, providing land for agriculture, human settlements, and resources like minerals.
• Hydrosphere: All the water bodies on Earth, essential for drinking, agriculture, and supporting aquatic life.
• Atmosphere: The layer of gases surrounding Earth, protecting life from harmful solar radiation and providing oxygen for respiration.
• Biosphere: The zone where life exists, including all living organisms that interact with the physical environment.
• Human-made environment: Includes structures like buildings, roads, and industries created by humans to meet their needs.
• Natural environment: Comprises the Earth's natural features like mountains, rivers, forests, and ecosystems.

Q12: Explain the importance of ecosystems and the impact of human activities on them. (5 Marks)

Ans:

• Ecosystems are communities of living organisms interacting with their physical environment. They provide essential services like pollination, water purification, and nutrient cycling.
• Ecosystems support biodiversity, ensuring a balance between producers, consumers, and decomposers.
• Deforestation, urbanization, and industrialization disrupt ecosystems, leading to habitat destruction and loss of species.
• Human activities like pollution contaminate air, water, and soil, affecting the health of ecosystems.
• Climate change, driven by human actions, alters ecosystems, forcing species to migrate or face extinction.
• Conservation efforts are necessary to protect ecosystems and ensure the sustainable use of resources for future generations.

Q13: Discuss the relationship between humans and the natural environment, and the need for balance. (5 Marks)

Ans:

• Humans depend on the natural environment for essential resources like air, water, food, and shelter.
• Human activities like agriculture, industrialization, and urbanization often modify or damage the environment.
• Over-exploitation of natural resources, such as deforestation and mining, leads to environmental degradation.
• Pollution from human activities impacts the air, water, and soil, threatening the survival of plants, animals, and humans.
• A balance between human activities and the natural environment is crucial for maintaining biodiversity and ecological stability.
• Conservation efforts, such as reforestation, sustainable farming, and reducing pollution, are necessary to protect the environment.
• Humans must learn to live in harmony with nature, ensuring that their needs do not lead to the destruction of ecosystems.
• Renewable resources like solar energy and wind power offer sustainable alternatives to reduce the environmental impact.
• Laws and policies promoting environmental protection are essential to limit human activities that harm the environment.
• Education and awareness about the importance of the environment can help individuals make more eco-friendly choices.
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