Question

In a resting person, oxygen saturation of haemoglobin as blood leaves the tissue capillaries is?

• A. $3\%$
• B. $40\%$
• C. $46\%$
• D. $75\%$

Answer 1

The correct option is D $75\%$

The partial pressure in deoxygenated blood returning from body tissue is about 40mm Hg and at this PO2​​, the saturation of haemoglobin is about 70 to 75%.

So, the correct answer is '75%