Varicose veins are caused by:
A) a loss of elasticity in blood vessels
B) the accumulation of fatty substances within blood vessels
C) excessive production of the enzyme renin
D) incompetent venous valves
E) orthostatic hypotension
Answer: D
Varicose veins are caused by:
A) a loss of elasticity in blood vessels
B) the accumulation of fatty substances within blood vessels
C) excessive production of the enzyme renin
D) incompetent venous valves
E) orthostatic hypotension