Which of the following occurences would most likely result in an increase in
allele frequencies in a population?

it's c.us forest service

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.  

d. changes in climate and historical records

hope this