The most critical defining characteristic of a true experiment is often seen to be a high degree of control over the
a. arrangement of experimental conditions.
b. choice of dependent variables.
c. random assignment of participants to experimental conditions.
d. systematic manipulation of independent variables.

Option (c) is correct.

From the given options, the most decisive peculiarity of a true experiment is given as follow: "generally seen to be a high rate of control over a random assignment of individuals to experimental circumstances.

Thus the correct option in this particular case is (C).

manifest functions are the recognized and intended consequences of any social pattern, while latent functions are those unrecognized and unintended consequences. to analyze the manifest functions of any social institution, we have to study its contribution to the continuation of a group, community, or society.

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."