Mammalian RBCs are ______ in shape -

Options

A. Oval
B. Biconvex
C. biconcave
D. Sickle like

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of Mammalian RBCs**:
- Mammalian red blood cells (RBCs) are unique in that they lack a nucleus (enucleated). This absence of a nucleus is crucial for their function and shape.

2. **Shape of Mammalian RBCs**:
- The shape of mammalian RBCs is described as bi-concave. This means that the cells are curved inward on both sides, resembling a doughnut without a hole.

3. **Reason for the Bi-concave Shape**:
- The bi-concave shape increases the surface area-to-volume ratio of the RBCs, which is essential for efficient gas exchange (oxygen and carbon dioxide) as they travel through the bloodstream.

4. **Conclusion**:
- Therefore, the correct answer to the question is that mammalian RBCs are bi-concave in shape.

**Final Answer**: Mammalian RBCs are bi-concave in shape.

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