How long do scientists estimate that the sea has been at its current level? a. 250 years b. 2,500 years c. 25,000 years d. 250,000 years

d. 250000 years is the answer

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.