Which is an example of a density-independent factor? A. limited water for plants
B. limited prey for predators
C. a fixed amount of grass for cows
D. a hurricane

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; incomplete dominance;

answer; behavioral neuroscience;