Hemophilia is an X-linked recessive trait. If a female carrier for hemophilia marries a normal male. If they produce a son, what are the chances he will have hemophilia

50%

Explanation:

The punnet square shows that the genotypes for males would be  X^HY which doesn't have Hemophilia and X^hY which has Hemophilia, meaning for males there is a 50% chance of getting it.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the missing space is phylum