There is some liquid in a closed bottle. The amount of liquid is continuously decreasing. The vapour in the remaining part

1.  must be saturated

2.  must be unsaturated

3.  may be saturated

4.  there will be no vapour. 

There is some liquid in a closed bottle. The amount of liquid remains constant as time passes. The vapour in the remaining part:
1. must be saturated.
2. must be unsaturated.
3. maybe unsaturated.
4. there will be no vapour.

In a room containing air, heat can go from one place to another:

In summer, a mild wind is often found on the shore of a calm river. This is caused due to:
a. the difference in thermal conductivity of water and soil.
b. convection currents.
c. conduction between air and the soil.
d. radiation from the soil.
Choose the correct option:
1. (a) , (b) 
2. (b)  only
3. (d) only 
4. (a) , (d)