if a mutation produces a new coat color in a fox population what factor might determine whether the frequency of that new trait will increase​

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.  

the answer is definitely a

answer; blending inheritnace;