Same chapter3 marksDifficulty: Medium
Explain why a person of blood group O is called a universal donor.
Circulatory System
3 marksDifficulty: Medium
What is double circulation and why is it necessary?
Original Khojo Papers practice question — not from a past board paper.
Answer
Double circulation means the blood passes through the heart twice in one complete circuit of the body: once through the pulmonary circulation to the lungs, and once through the systemic circulation to the rest of the body. It is necessary because it keeps oxygenated and deoxygenated blood completely separate and lets the blood be pumped to the body at high pressure after it has been oxygenated.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Fish, with a two-chambered heart, have single circulation.
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