Burning of wood returns carbon primarily to the (A) animals (B) water (C) plants (D) atmosphere​

B

Explanation:

The smoke from the burning wood travels into the air which affects the atmosphere more than anything else.

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.