4.3   Additional Questions :

Answer the following questions :

1.  What is the significance of the greenhouse gas ?
Ans: Without the greenhouse gas the earth would have been too cold to live in.

2.  How does carbon dioxide create greenhouse gas ?
Carbon dioxide creates greenhouse effect by trapping the heat radiated from the earth.

3.  What happens when air is heated ?
 When air is heated, it expands , becomes lighter and goes up.

4.  What is temperature ?
The degree of hotness and coldness of the air is known as temperature.

5.  What is isolation ?
Isolation is the incoming  solar energy intercepted by the earth.

6.  How does air move ?
Air moves from high pressure areas to low pressure areas.

7.  How do bacteria help plants use nitrogen ?
Bacteria that live in the soil and roots of some plants, take nitrogen from the air and change its form so that plants can use it.