Question

A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues. This O₂

• A. Helps in releasing more $O_{2}$ to the epithelial tissues.
• B. It is enough to keep oxyhaemoglobin saturation at $96 \%.$
• C. Raise the $p C O_{2}$ of blood to 75 mm of Hg.
• D. Acts as a reserve during muscular exercise

Answer 1

Answer: (D)

A large portion of the oxygen is left unused in the human blood even after its uptake by the body tissues. This $O_{2}$ acts as a reserve during muscular exercise. Tissues usually take up only 25% of the oxygen in the tissue and the rest 75% remain unused in the blood (venous).