The Term "Double Muscling" Refers to

The term "double muscling" refers to

A) mutations in the myostatin gene that lead to increased muscle mass in cattle.
B) mutations in the CACNA1D gene involved in heart function that lead to increased muscle mass in mice.
C) mutations in the gene for growth hormone that lead to increased muscle mass in dogs.
D) mutations in a gene that lead to decreased muscle mass in cattle.
E) all of these.