Every friday, dr. cruz would give a quiz in his psychology class. students quickly learned to be nervous on friday mornings, just before each quiz. halfway through the semester, dr. cruz stopped giving quizzes on fridays and the students' anxiety began to diminish with each passing week in which there was no quiz. the decrease in the students' anxiety may be attributed to the process of:
a. spontaneous recovery.
b. extinction.
c. stimulus generalization.
d. latent learning.

Which of these describes a social effect of the civil war? a) fields were left unplanted because the slaves had been freed and much of the male population was unavailable to plant or harvest crops. b) over 600,000 men died, mostly because of the lack of food, clean water, and hygienic medical practices. c) after the emancipation proclamation was issued, african americans were allowed to join the union army. d) lincoln’s assassination after the surrender caused a disruption in the rebuilding of the nation.