The transfer of heat energy in a liquid or gas through the motion of the liquid or gas caused by differences in density is called?*

O Conduction
O Convention
O Concentration
O Convection

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it

it's false. hope i .

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.