Which of the following would be a reason for a species to undergo cyclic population changes?
a. the keystone species in its ecosystem is removed.
b. the vegetation it eats increases and then decreases repeatedly with changing seasons.
c. its predator is preyed upon by a new species introduced to the ecosystem.
d. climate change alters the prevalence of parasites that affect the species.

Read the scenario below and answer the question that follows. hallie is reading a novel in the library when susan, her best friend, slumps down in a chair next to her. susan doesn't say anything, but hallie knows that susan is upset because she is slumping in her seat and rolling her eyes. a psychologist would explain that hallie is interpreting her friend's emotion based on a. the behavioral component of emotion b. her friend's ability to regulate emotion c. the verbal component of emotion d. the physiological component of emotion select the best answer from the choices provided a b c d