Which of the following symbols are used for represeting sex chromosomes of birds ?

Options

A. `Z Z-ZW`
B. `XX-XY`
C. `XO-XX`
D. `ZZ-WW`

Answer

To answer the question regarding the symbols used for representing sex chromosomes of birds, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Sex Determination**:
- In many organisms, sex determination is a genetic process where males and females have different alleles or genes that define their sexual characteristics.

2. **Identifying the Sex Chromosomes in Birds**:
- In birds, the sex determination system is different from that of mammals. Birds use a system known as the ZW system.
- In this system, males are represented by the homozygous ZZ configuration, while females are represented by the heterozygous ZW configuration.

3. **Conclusion**:
- Therefore, the symbols used for representing the sex chromosomes of birds are ZZ for males and ZW for females.

4. **Final Answer**:
- The correct answer is that the sex chromosomes of birds are represented by the symbols **ZZ and ZW**.