In birds, femals are reprsented by chromsome

Options

A. XX
B. ZZ
C. ZO
D. ZW

Answer

To answer the question about the representation of female chromosomes in birds, we can break down the information step by step.

### Step-by-Step Solution:

1. **Understanding Chromosome Representation**:
- In birds, the sex determination system differs from that of mammals. While humans have an XX/XY system, birds utilize a ZW/ZZ system.

2. **Identifying Female Chromosomes**:
- In this ZW system, females are represented by the ZW combination. This means that female birds have one Z chromosome and one W chromosome.

3. **Identifying Male Chromosomes**:
- Conversely, male birds are represented by the ZZ combination, meaning they have two Z chromosomes.

4. **Heterogametic vs. Homogametic**:
- In this system, females are heterogametic (ZW), as they produce two types of gametes (Z and W). Males, being homogametic (ZZ), produce only one type of gamete (Z).

5. **Conclusion**:
- Therefore, the correct representation of female chromosomes in birds is ZW.

### Final Answer:
In birds, females are represented by the chromosome combination **ZW**.

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