Final answer:
The physical change that does not occur in middle adulthood is the accumulation of muscle mass; instead, muscle mass tends to decrease.
Other changes, such as a decline in visual acuity, loss of skin elasticity, and slowing of the nervous system, do occur in middle adulthood.
Step-by-step explanation:
The physical change that does NOT occur in middle adulthood is the accumulation of muscle mass. During middle adulthood, which extends from the 40s to the 60s, there is generally a gradual physical decline. The skin loses some elasticity, visual acuity decreases, and there are changes in weight distribution.
Contrary to muscle mass increasing, a condition known as sarcopenia may start to develop in late adulthood, characterized by a gradual decrease in skeletal muscle mass. Middle-aged adults often experience loss of muscle mass rather than an accumulation. Furthermore, the nervous system begins to slow down, but this process continues more noticeably into late adulthood.
The physical change that is NOT one of the changes that occur in middle adulthood is a) Accumulation of muscle mass. Middle adulthood is the stage when physical signs of aging start to appear, such as wrinkling, gray hair, and decline in visual acuity.
The skin loses elasticity, and there is a slowing of the nervous system. However, there is a decline in muscle mass rather than an accumulation.