Dr. su was conducting a study on a new antidepressants. Half of the participants were given the new drugs and the other half were given placebo. what procedure did Dr. su use to treat both groups excatly the same and not inadvertently influence the results

a. the moon was locked into orbit by the earths gravity as it was passing by and capture hypothesis i think

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."

protectionism fosters competition and keeps price regulated is not an argument in favor of protectionism.