hemophilia is a bleeding disorder that primarlily affects males. which of the following statements best explains why females are less likely to exppress the trait?

Question

when paired witth a normal X, the affected x allel is masked (Xx), suppressing the trait. since females have only X alleles, the probability increases.
females have an XY chromosome pair, so the trait is frequently expressed
males without an affected x allel always express the trait (XY)
when paired with a normal X, the affected x allele is masked (Xx), suppressing the trait. Since females have only X alleles, the probability decreases.

Answer 1

The best statement that explains why females are less likely to express hemophilia is:

"When paired with a normal X, the affected X allele is masked (Xx), suppressing the trait. Since females have two X chromosomes, the probability decreases."

This is correct because females have two X chromosomes (XX). If one X chromosome carries the hemophilia allele (let’s denote it as \(X^h\)), the other normal X chromosome (denote it as \(X\)) can mask the effect of the hemophilia allele, leading to a condition known as being a carrier (Xx) rather than expressing the disorder. In contrast, males have only one X chromosome and one Y chromosome (XY), so if their sole X chromosome has the hemophilia allele, they will express the disorder.