Which of the following is the most cost-effective approach to waste management? A) pollution-prevention control
B) chemical emissions control
C) biological environment control
D) physical containment control

i believe your answer would be c.. : )

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.