If a man from the sea coast goes to the Everest peak,then:

$I.$ $pO_2$ is the major factor which affects the binding of $CO_2$ with haemoglobin.
$II.$ $pCO_2$ is low and $pO_2$ is high in tissues.
$III.$ $RBC$ contains a very high concentration of carbonic anhydrase.
$IV.$ Every $100 \; mL$ of deoxygenated blood delivers approximately $4 \; mL$ of $CO_2$ to alveoli.
Select the combination of right statements.

Which physiological adaptation occurs in people living at high altitudes to survive in low atmospheric pressure?

If a large number of people are enclosed in a room,then

At high altitudes,the number of red blood cells in humans:

Which of the following is a respiratory gas?