Quotations 16 to 20 based on the following passage:

　　At the end of the 7 weeks, the step-test was again given to both groups of subjects, and their pulses taken. he post-exercise pulse rates of subjects in the experimental group were found to have decreased an average of 30 heart beats per minute, with the lowest deceased 28 and the highest decrease 46. The pulse rate of subjects in the control group remained the same or changed no more than 4 beats, with an average difference between the initial and final tests of zero.

( ) 16. The step-test was given

A) after each exercise period

B) at the beginning and at the end of the seven week period

C) only once, at the beginning of the seven week period

D) twice to the men in Group A and once to the men in Group B

( ) 17. When were pulse rates taken?

A) After every exercise period.

B) Every day.

C) After the step-tests.

D) Every time the ratio of active riding was increased.

( ) 18. The exercise schedule was planned so that the amount of active riding

A) increased every few days

B) varied from day to day

C) increased until the third week and then was kept constant

D) increased every exercise period

( ) 19. What did Group A do in their program?

A) They stepped up and down on a bench each day

B) They pushed and pulled on exercise handles every day

C) They refrained from any exercise

D) They rode on an Exercycle every day

( ) 20. This paragraph implies that

A) most people do not get enough exercise

B) a high pulse rate is desirable

C) regular exercise can strengthen your heart

D) everyone should exercise 15 minutes a day