1. carrying capacity
A. one example of a density-independent limiting factor is
B. the number of individuals of a single species per unit area is known as
C. the maximum number of organisms of a particular species that can be supported by an environment is called
D. the movement of individuals into an area is called

what's the question?

well, i believe that the answer is 2. : 3

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.