The number of $RBC$ in a man increases if he lives at a higher altitude because:

Which of the following is correct regarding the partial pressures of gases ($PO_2$ and $PCO_2$) in different parts of the human respiratory system?

Constant flow of $CO_2$ from the tissues into the blood is due to

What does the presence of a large number of alveoli around the alveolar duct opening into the bronchioles in mammalian lungs indicate?

People living at sea level have around $5$ million $RBC$ per cubic millimeter of their blood,whereas those living at an altitude of $5400$ metres have around $8$ million. This is because at high altitude:

The exchange of gases in the alveoli of the lungs occurs by .............