During Middle Adulthood, Aerobic Capacity Declines as ______

Multiple Choice

During middle adulthood, aerobic capacity declines as ______.

A) less oxygen is taken into the lungs and less blood is pumped by the heart
B) sensitivity to insulin is lost by the muscle tissues
C) lean-body mass, which includes fat, is replaced by muscle
D) large amounts of calcium are lost by the bones, making them porous and brittle