Hulk often has to step in and solve disagreements between his son Hogan and his daughter Brooke. This action best reflects the idea of a parent as a

a. playmate

Correlation does not imply causation. We know this because two main drawbacks of correlation studies are

a. poor correlation coefficients and alpha rankings. b. third variable problem and directionality. c. magnitude and direction of the correlation. d. moderate association and fictional dependence.

The amino acid tryptophan is the precursor to which neurotransmitter?

a. dopamine b. endorphin c. serotonin d. nitric oxide