What is the respiratory rate in a rabbit?

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

What is the last step involved in respiration?

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

What is the respiratory rate in a newborn baby compared to an adult?

Choose the correct option:
$(1)$ On an average,a healthy human breathes ...$X$... times/minute.
$(2)$ Every $100 \, ml$ of oxygenated blood can deliver around ...$Y$... of $O_2$ to the tissues under normal physiological conditions.
$X-Y$