8. What animal group(s) have opposable thumbs and binocular vision?
A) all primates
c) humans only
B) hominids
D) monkeys only

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

answer; an inhibitory postsynaptic potential;