Textbook Solutions: Our Environment | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

A. Choose the correct answer

1.
Ans: (a)

2.
Ans: (b)

3.
Ans: (a)

4.
Ans: (d)

5.
Ans: (b)

B. Fill in the blanks

1.
Ans: Our environment comprises both living and non-living things.

2.
Ans: The physical environment consists of the lithosphere , hydrosphere and atmosphere.

3.
Ans: The Greek word 'lithos' means stone .

4.
Ans: The biological environment is also known as the biosphere.

5.
Ans: In an ecosystem, everything is closely interconnected.

C. Answer in one or two sentences

1.
Ans: The environment is everything that surrounds us, including both living and non-living components, some of which are natural like trees, mountains, lakes, and others that are human-made such as parks, roads, and vehicles.

2.
Ans: The lithosphere is the hard, outermost layer of the Earth, also known as the crust, which is made up of rock and consists of different landforms like mountains, plateaus, and plains.

3.
Ans: The function of the atmosphere in the environment is to provide living organisms with life-supporting gases and to help control the Earth's temperature.

4.
Ans: The biosphere, or the biological environment, is a narrow zone where the lithosphere, the hydrosphere, and the atmosphere come into contact and where all life exists.

5.
Ans: The socio-cultural environment consists of family, religion, education, the customs, and the beliefs of the people living in an area, providing the environment or surroundings in which people grow up and live.

6.
Ans: Two factors that have contributed to environmental degradation are widespread deforestation and pollution.

D. Answer In a paragraph

1.
Ans: The physical environment consists of naturally occurring non-living things like land, water, or air, and includes the lithosphere, hydrosphere, and atmosphere. The biological environment or the biosphere is where the physical environment components interact and where all life exists, leading to the formation of ecosystems. In contrast, the built-up environment is a part of the human environment and consists of physical things created by humans, such as houses, factories, farms, and transport networks.

2.
Ans: An ecosystem is a system formed by a community of interdependent living organisms and their interaction with the environment. It can be as large as a rainforest or as small as a rotting tree trunk. For instance, in the ecosystem of a rotting tree trunk, the decaying tree provides food for mushrooms and other fungi, which in turn provide food for insects. These insects are eaten by frogs and lizards, which are then eaten by snakes. If any element of this chain is affected or removed, the entire ecosystem is affected.

3.
Ans: Over the years, humans have significantly impacted the environment, often negatively, by altering it to suit their needs. They have built wells, dams, canals, cleared forests to plant crops, and build houses and factories. This has led to widespread pollution and destruction of the natural environment, causing problems like global warming, destruction of ecosystems, and extinction of animals. To protect the environment, it is crucial to balance the natural and human environment and use natural resources judiciously.