American bullfrog major physical structures and coloring

green or greenish brown

Explanation:

it has strong, long back legs with webbed feet.the back and sides may be plain or may have dark spots. The arms and legs are spotted or barred with dark. Underparts are white, distinctly or obscurely spotted and mottled.

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.