Select the correct match.

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

$A$: When a person starts doing exercise,the rate and depth of breathing increase even before there are changes in $pO_2$,$pCO_2$,or $H^+$ concentration.
$R$: The main stimulus for these quick changes is due to input from the proprioreceptors,which monitor movements of joints and muscles.

Whales are air-breathers but can live underwater for a long time because they possess:

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

In most of the thin-leaf mesophytes,the leaf stomata open during the day and close during the night. This pattern is known as: