If two eggs are released from the mother's ovary, and both are fertilized and develop simultaneously, the result is a pair of monozygotic twins

A man is on a diet-and-exercise program. Whenever he loses a pound of body fat, he puts $10 aside to be used to buy himself new golf clubs. The man is taking part in what behavior therapists would call

a. a positive reinforcement strategy. b. shaping. c. aversion therapy. d. systematic desensitization.

The probability that an experimenter's results are due to chance is called the ________

a. significance b. variance c. correlation coefficient d. normal distribution