Twin studies indicate that the heritability of major depressive disorder is around:

In the peripheral nervous system, _______________ enable us to move, and cause glands to contract and to secrete hormones

a. motor nerves b. glial cells c. dendrites d. sensory nerves

Ivan is stingy, obstinate, overly precise, and excessively orderly. In Freud's view, he is probably fixated in the ______ stage

a. anal c. genital b. oral d. phallic