Because natural selection over time cancels a species or makes them scarce, showing how nature can work in favor of certain traits over others. Since some will become low in a trait, then over time the mating will result in more and more of the desired trait. And this is evolution: change in allele frequency over a long period of time.
Answer:
from his mother
Explanation:
because they have one copy of X chromosome from their mother and if X chromosome have DMD gene mutation so he will have DMD