Francine is emotionally mature. She has broad practical knowledge and is able to apply that knowledge in ways that make life worthwhile. Francine displays

A dog learns to "shake paws" on command because it has been given dog biscuits for doing so. This is an example of

classical conditioning. operant conditioning. cognitive conditioning. stimulus conditioning.

Prolonged stress leads to suppression of the immune system. What might explain the evolution of such a seemingly flawed reaction?

a. There is no reasonable explanation for this. b. Susceptibility to disease would increase the likelihood of an early death. c. Immune suppression has no lasting effects on overall health. d. Such immune suppression might prevent the development of autoimmune illnesses.