Suppose you and your roommate have the following agreement when it comes to cleaning your apartment: each person washes her or his own dishes after each meal. the principle of trade you just learned tells you that it would be more efficient if: a) both of you wash your own dishes after each meal. b) neither of you wash the dishes after eating. c) each of you wash half of all the dirty dishes. d) one of you wash all the dishes while the other does a different chore.

D

Explanation:

The principle of trade you just learned tells that it would be more efficient if they both do their divided work. There are some tricks of the trade that you can use in cleaning your own house:

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."

answer; make a no-nonsense accusation of the other;