Oxytocin helps . a. people who have trouble recognizing expressions, helping them mainly with fairly easy expressions b. everyone with recognizing fairly difficult expressions c. people who have trouble recognizing expressions, helping them mainly with fairly difficult expressions d. everyone with recognizing only fairly easy expressions

"d.) carbon dioxide and hydrogen sulfide"

what in the weirdo : o

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.