Answer:
The correct answer is - hemophilia is the x-linked chromosome disease that is not present and this trait is not present in the mother (Helena).
Explanation:
Hemophilia is the sex-linked chromosome diseases that move from one generation to the other and usually occur in the male offspring in comparative females as they are carriers for disease.
This disease does not carry by the y chromosome and the mother of both Charles and Alexander did not carry the hemophilia trait, so both did not have the diseased or affected chromosome.
Thus, the correct answer is - hemophilia is the x-linked chromosome disease that is not present and this trait is not present in the mother (Helena).
