8. Morgan usedcrosses to study a new pattern of inheritance.​

Pretty sure he used female gametes

i think the answer is a.keratin is the pigment responsible for skin color.

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.