Environment

1. Ecosystem is the system formed by the interaction of all living things with one another and with the physical and chemical factors of the environment in which they live linked by transfer of energy and material.
2. By natural environment we mean the surroundings created by the nature. It comprises of the objects such as - mountains, plateaus, plains, valleys, forests, land, air, river, ocean, water and all living and non-living things etc.
3. Major components of the environment include – Natural Components like, Land (Lithosphere), Water (Hydrosphere), Air (Atmosphere), Living things (Organism).Human made Components like, buildings, parks, bridge, road, industries etc.Humans like, individuals, family, community, religion, politics, education
4. Examples of human made environment are like, buildings, parks, bridge, road, industries etc.
5. Lithosphere is the hard top layer of the earth or crust consisting of rocks and minerals extending both over the continents and ocean basins.
6. The two basic components of biotic environment are: Plants and Animals
7. Biosphere: Plants and animals found in the narrow strip at the junction of lithosphere, atmosphere and hydrosphere together make biosphere.

1-d, 2-a, 3-b, 4-c.

a. It is true that man modifies his environment. It is because –

• He uses water.
• Deforestation by which he clears land for agriculture, industries and habitation
• He tills land for agriculture.
• He uses air.
• Numerous activities made to make the life comfortable.

b. The interdependence of plants and animals can be illustrated by the following points:

• Plants provide food to animals.
• Forests provide shelter to wild life.
• Wildlife adds beauty to forests.
• Animal dung provides manure for the growth of plants.
• The decay of dead animals provides nutrition to soil which in turn helps in the growth of plants and trees.