The answer to this question is:
a) RBCs are biconcave disks with a healthy concentration of 4-6 million per mm³ in males and 4-5 million per mm³ in females.
Let's break this down step-by-step:
1. Shape of RBCs: Red Blood Cells (RBCs) are described as biconcave disks. This unique shape increases their surface area to volume ratio, which is essential for efficient gas exchange.
2. Healthy Concentration: The concentration of RBCs in blood is generally measured in terms of cells per cubic millimeter (mm³). For males, a healthy concentration ranges from 4 to 6 million RBCs per mm³, whereas for females it typically ranges from 4 to 5 million RBCs per mm³.
3. Options Analysis:
- Option a) correctly identifies both the biconcave shape of RBCs and provides the healthy concentration ranges for males and females.
- Option b) incorrectly states that RBCs are spherical, which they are not.
- Option c) mentions that RBCs form 40-50% of the formed elements in blood, but this percentage more accurately refers to the hematocrit, not the specific healthy concentration in cells per mm³.
- Option d) incorrectly states that RBCs are oval-shaped.
Thus, the best description is given by option (a).
