Which statement best describes erythrocytes (red blood cells) in humans?

• A. They are biconcave, anucleate cells specialized for transporting oxygen via hemoglobin.
• B. They are large granulocytes that release histamine during allergic reactions.
• C. They are cell fragments responsible for blood clotting and wound repair.
• D. They are nucleated cells that leave capillaries to become macrophages in tissues.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure and function of erythrocytes (red blood cells). Erythrocytes are specialized cells in the blood primarily responsible for transporting oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs.
2. Step 2: Recall the unique shape of erythrocytes. They have a biconcave disc shape, which increases their surface area for gas exchange and allows them to deform as they pass through narrow capillaries.
3. Step 3: Note the absence of a nucleus in mature erythrocytes. This anucleate condition provides more space inside the cell for hemoglobin, the oxygen-carrying protein.
4. Step 4: Differentiate erythrocytes from other blood cells. For example, granulocytes are white blood cells involved in immune responses, platelets are cell fragments involved in clotting, and macrophages are nucleated cells derived from monocytes that function in phagocytosis.
5. Step 5: Conclude that the best description of erythrocytes is that they are biconcave, anucleate cells specialized for transporting oxygen via hemoglobin.