Select the incorrect statement :

Options

A. Human males have one of their sex-chromosome much shorter than the other.
B. Male fruit fly is heterogam,etic.
C. In male grasshoppers, 50% of sperms have no sex chromosome.
D. In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.

Answer

To determine the incorrect statement regarding sex determination, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: "In human males, one sex chromosome is smaller than the other."
- **Analysis**: This statement is correct. In humans, males have one X and one Y chromosome (XY). The Y chromosome is smaller than the X chromosome.

2. **Statement 2**: "Male fruit fly is heterogametic."
- **Analysis**: This statement is also correct. In fruit flies (Drosophila), males have XY sex chromosomes, making them heterogametic as they produce two types of gametes (X and Y).

3. **Statement 3**: "In male grasshopper, 50% of the sperm does not have any sex chromosome."
- **Analysis**: This statement is correct. In grasshoppers, the male has an XO sex determination system, meaning that half of the sperm will have the X chromosome, and the other half will have no sex chromosome.

4. **Statement 4**: "In domesticated fowl, the sex of progeny depends on the type of sperm, not on the egg."
- **Analysis**: This statement is incorrect. In birds, the sex determination system is ZW, where females are heterogametic (ZW) and males are homogametic (ZZ). The sex of the progeny depends on the type of egg (ZW) produced by the female, not on the sperm.

### Conclusion:
The incorrect statement is **Statement 4**: "In domesticated fowl, the sex of progeny depends on the type of sperm, not on the egg."

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