Question

The mountaineers carry oxygen with them because:
a. at an altitude of more than 5 km there is no air.
b. the amount of air available to a person is less than that available on the ground.
the temperature of air is higher than that on the ground.
d. the pressure of air is higher than that on the ground.​

Answer 1

Answer:

The atmospheric pressure goes on decreasing as we go up above the sea level, and the amount of oxygen also decreases at higher altitude.

So the correct option is 'The amount of air available to a person is less than that available on the ground