Mountaineers carry oxygen cylinders with them because

Options

A. there is no oxygen on high mountains.
B. there is deficiency of oxygen on mountains at high altitude.
C. oxygen is used for cooking.
D. oxygen keeps them warm at low temperature

Answer

B

Explanation

The reason behind carrying the oxygen is when they climb mountains, as altitude increases, the amount of oxygen level in the atmospheric air decreases as there are no trees found on the higher altitude to supply the oxygen. In such a case, mountaineers suffer from dizziness because of hypoxia.