Explain why endangered species are more at risk for losing genetic diversity than a species with very large numbers of individuals.

the answer is c) an oak tree

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.