Which one is enucleated?

Options

A. Squamous epithelial cells
B. Mature leucocyte of man
C. Mature erythrocyte of frog
D. Mature erythrocyte of man

Answer

To determine which cell type is enucleated, we need to understand what enucleation means and examine the options provided.

### Step-by-Step Solution:

1. **Understand Enucleation**: Enucleation is the process by which a cell loses its nucleus. This typically occurs in certain types of cells as they mature.

2. **Analyze the Options**:
- **A. Squamous epithelial cells**: These cells are part of the epithelial tissue and contain a nucleus. Therefore, they are not enucleated.
- **B. Mature leucocytes of man**: Leucocytes, or white blood cells, are involved in the immune response and retain their nuclei even in their mature form. Thus, they are not enucleated.
- **C. Mature erythrocytes of frog**: While frog erythrocytes do lose their nuclei during maturation, the question specifically asks for human cells.
- **D. Mature erythrocytes of man**: In humans, mature red blood cells (erythrocytes) are indeed enucleated. They lose their nucleus during maturation to maximize space for hemoglobin, which is essential for oxygen transport.

3. **Conclusion**: Based on the analysis, the correct answer is **D. Mature erythrocytes of man**.

### Final Answer:
**D. Mature erythrocytes of man**

---