The hard flat plates of keratin that cover the tips of the fingers and toes are the:

i believe it is c: genes for body color and wing size are inherited separately from each parent.

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.