How big are red blood cells in diameter?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 7.5 μm.
Red blood cells (RBCs) have an average diameter of about 7.5 micrometers (μm). This small size is essential for their function in the body, allowing them to pass through even the narrowest capillaries and efficiently transport oxygen from the lungs to tissues and carbon dioxide back to the lungs for exhalation. The biconcave shape of RBCs also helps increase their surface area, facilitating effective gas exchange.