Comparative psychologists usually compare

A) cross-cultural differences in I.Q. scores.
B) tests that measure different forms of mental illness.
C) the behaviors of children of different ages.
D) the behaviors of different species of animals.

Comparative Psychologists

Researchers who study the behavior and mental processes of non-human animals in comparison to humans, to understand psychological phenomena across species.

Cross-Cultural

Pertaining to or comparing the cultural differences, practices, and norms between different societies or ethnic groups.

Mental Illness

Health conditions involving changes in emotion, thinking, or behavior (or a combination of these), associated with distress or problems functioning in social, work, or family activities.