Duchenne Muscular Dystrophy (DMD) is a sex-linked trait that causes muscular weakness that gets worse as a person ages. Which is most likely true of Duchenne Muscular Dystrophy? A. DMD can only be inherited by females. B. Females with DMD always have a mother with DMD. C. The gene for DMD is located on the X or Y chromosome. D. The gene for DMD is most active in the cells of the reproductive organs.

C

Explanation:

DMD is s*x linked trait. This means that we have to consider the   chromosomes XX and XY. For a male to have DMD, this means the mom must must pass down the allele for DMD. The mom can either be a carrier OR she has to have DMD and the dad can only pass down the Y chromosome. For a daughter to get DMD, this means the dad has to have the allele for DMD and so does the mom. That means that the dad has DMD and the mom can either have DMD or be a carrier. Based off of this logic, we know that the answer isn't B.  Because they tell us DMD is s*x-linked trait, it means that the gene for DMD is on the x or y chromosome.