How is greenhouse effect related to global warming? Explain.

2

(a)

Name any two environmental problems caused by various activities of human beings.

2

(a)

How the biosphere is a dynamic and stable system?

2

(a)

How is our atmosphere different from the atmospheres on Venus and Mars?

2

(a)

How does the atmosphere act as a blanket?

2

(a)

Which symbiotic life forms can grow on stones and help in the formation of soil? Write the mode of their action for making soil from rocks. 

2

(a)

What factors decide the type of soil?

2

(a)

What is top soil? Mention any two factors that decide which plants will thrive on that soil.

2

(a)

What are the causes of soil erosion?

2

(a)

What is soil erosion? Give two methods of reducing it.

2

(a)

List the important steps involved in nitrogen cycle in the biosphere.

2

(a)

Burning of fossil fuels causes pollution, Comment.

2

(a)

Write the harmful effects of ozone depletion.

2

(a)

Why do terrestial life forms require fresh water?

2

(a)

If decomposers are removed completely from the Earth, what will be the result? Give reasons.

2

(a)