Why is the father’s contribution considered decisive for sex determination in humans compared with the mother’s?
Answer and explanation
Correct answer: The mother always contributes X, while the father can contribute either X or Y
In the usual human chromosomal system, the mother is XX, so every ovum carries an X chromosome. The father is XY, so sperm may carry either X or Y. Fertilisation by an X-bearing sperm produces XX, while fertilisation by a Y-bearing sperm produces XY. Therefore option A is correct. The mother contributes a chromosome, and the other options incorrectly deny chromosomal determination or the father’s two sperm types.
Frequently asked questions
What is the correct answer to this question?
The mother always contributes X, while the father can contribute either X or Y
Why is this the correct answer?
In the usual human chromosomal system, the mother is XX, so every ovum carries an X chromosome. The father is XY, so sperm may carry either X or Y. Fertilisation by an X-bearing sperm produces XX, while fertilisation by a Y-bearing sperm produces XY. Therefore option A is correct. The mother contributes a chromosome, and the other options incorrectly deny chromosomal determination or the father’s two sperm types.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Heredity and Evolution. Topic: Sex determination.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
