Assertion :- Egg is responsible for sex of the chicks & not the sperm.
Reason :- Birds shows female heterogamety.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are trur but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is Flase.
D. If both Assertion & Reason are false.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Egg is responsible for the sex of the chicks and not the sperm." This implies that the sex of the offspring (chicks) is determined by the genetic material present in the egg.

2. **Understanding the Reason**:
- The reason states that "Birds show female heterogamety." In birds, the female has two different sex chromosomes (ZW), while the male has two of the same sex chromosomes (ZZ). This is known as female heterogamety.

3. **Linking Assertion and Reason**:
- In the case of birds, the female (hen) produces eggs that can carry either a Z or a W chromosome. The male (cock) produces sperm that can only carry a Z chromosome.
- Therefore, if the egg carries a Z chromosome, the resulting chick will be male (ZZ), and if the egg carries a W chromosome, the resulting chick will be female (ZW). This confirms that the egg indeed determines the sex of the chick.

4. **Conclusion**:
- Both the assertion and the reason are true. The reason correctly explains why the assertion is true: in birds, the sex of the offspring is determined by the type of egg produced by the female, which is a result of female heterogamety.

### Final Answer:
Both the assertion and the reason are true, and the reason is the correct explanation for the assertion.