Research indicates that setting more difficult goals for oneself ...

[APUS57]

Research indicates that setting more difficult goals for oneself
 
  a. results in higher performance.
  b. is likely to result in earlier withdrawal of effort.
  c. leads to lower performance than the goal of doing your best.
  d. All of these answers are correct.

Question 2

Over a two-week period, higher serotonin levels were associated with
 
  a. higher levels of both positive and negative feelings.
  b. lower levels of both positive and negative feelings.
  c. higher levels of positive feelings and lower levels of negative feelings.
  d. lower levels of positive feelings and higher levels of negative feelings.

[xiazhe]

Answer to Question 1

A

Answer to Question 2

B

[APUS57]

Excellent

[chjcharjto14]

Gracias!