Which of the following changes can result from intense exercise and training of an athlete?
A. Increased respiratory rate.
B. Increase in the size of muscle fibers.
C. Increase in the number of muscle fibers.
D. A and B.
Intense exercise and training of an athlete can result in a decreased respiratory rate and an increase in the size in muscle fibers. However, there will be no increase in the number of muscle fibers, since this does not change after birth.