Question

A large proportion of oxygen remains unused in the human blood even after its uptake by the body tissues. This $O_2$

• A. acts as a reserve during muscular exercise
• B. raises the $PC{O}_2$ of blood to 75 mm of Hg
• C. is enough to keep oxyhaemoglobin saturation at 96%
• D. helps in releasing more $O_2$ to the epithelial tissues.

Answer 1

Answer: (A)

acts as a reserve during muscular exercise

Out tissues usually take up approximately 25% of the oxygen in the tissue and the rest 75% remains unused in the blood. This remaining O2 acts as a reserve during muscular exercise.

So, the correct answer is 'acts as a reserve during muscular exercise'.