Dnar __________________________________________________

Blood vessels lose elasticity with age, leading to ____________________, which are most commonly seen in the legs because of the increased venous pressures in the legs from standing.

Fill in the blank(s) with the appropriate word(s).

The chemical messengers that stimulate the body's organs and help to maintain the body's internal environment (its milieu) are called ____.

A. hormones B. neurotransmitters C. steroids D. receptors