RBCs in human are :

Options

A. Biconcave and nucleated
B. Biconvex and nucleated
C. Biconvex and enucleated
D. Biconcave and enucleated

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of RBCs**: Red blood cells (RBCs), also known as erythrocytes, are specialized cells responsible for transporting oxygen throughout the body.

2. **Shape of RBCs**: RBCs are characterized by their unique biconcave shape. This means they are thinner in the center and thicker at the edges, resembling a doughnut without a hole. This shape increases their surface area, allowing for more efficient gas exchange.

3. **Nucleus Status of RBCs**: In humans, mature red blood cells are enucleated, meaning they do not contain a nucleus. This is an important adaptation that allows more space for hemoglobin, the protein that carries oxygen.

4. **Evaluating the Options**:
- **Option 1**: Biconcave and Nucleated - Incorrect, as RBCs are enucleated.
- **Option 2**: Biconvex and E-Nucleated - Incorrect, as RBCs are biconcave, not biconvex, and they are enucleated.
- **Option 3**: Biconvex and E-Nucleated - Incorrect for the same reasons as above.
- **Option 4**: Biconcave and E-Nucleated - Correct, as this accurately describes the structure of human RBCs.

5. **Conclusion**: The correct answer is option 4: Biconcave and E-Nucleated. This structure allows RBCs to maximize their oxygen-carrying capacity.

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