The statement Aging is not a uniform process in line 19 means that A. old people do not have the same outward signs of aging B. nerve cells and muscle fibers do not age simultaneously C.
The statement Aging is not a uniform process in line 19 means that __________
A. old people do not have the same outward signs of aging
B. nerve cells and muscle fibers do not age simultaneously
C. not all people age at the same age
D. the process of aging is slow