Non-nucleated erythrocytes are found in

Options

A. Fishes
B. Tadpole
C. Birds
D. Mammals.

Answer

To solve the question regarding where non-nucleated erythrocytes are found, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Erythrocytes**: Erythrocytes, or red blood cells (RBCs), are responsible for transporting oxygen in the blood. They can be classified based on the presence or absence of a nucleus.

2. **Identifying Types of Erythrocytes**:
- Non-nucleated erythrocytes are those that do not have a nucleus.
- Nucleated erythrocytes have a nucleus and are found in some animal groups.

3. **Analyzing the Groups Mentioned**:
- **Fishes**: Generally have nucleated erythrocytes.
- **Tadpoles**: Being amphibians, they also possess nucleated erythrocytes.
- **Birds**: Birds have nucleated erythrocytes.
- **Mammals**: Most mammals have non-nucleated erythrocytes.

4. **Conclusion**: Based on the analysis, non-nucleated erythrocytes are primarily found in mammals.

5. **Final Answer**: The correct answer to the question is that non-nucleated erythrocytes are found in **mammals**.