Which of the following is not an adaptation of skeletal muscle that would be observed in response to aerobic training?
a. an increase in mitochondrial densityb. an increase in capillary densityc. an increase in the number of oxidative fibersd. an increase in the diameter of the skeletal musclese. an increase in the concentration of oxidative enzymes.

an increase in the diameter of the skeletal muscles

Explanation:

The muscle adapts to aerobic exercise by an increase in mitochondrial density to provide enough energy to the cell through respiration, an increase in capillary density to supply nutrients to the tissues and increase blood flow, an increase in the number of oxidative fibers to help in energy regeneration and an increase in the concentration of oxidative enzymes.