In the United States, most emerging adults have at least STI[s] (sexually transmitted infection[s]).

im sorry i wish i can but try google

bro these r easy u may have to do them urself bro. lol jk the answer is two for nimber one, and for question number two sahel boi xd have fun get rekt m8

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."