When one animal attacks another, it engages in the most obvious example of aggressive behavior. Psychologists have adopted several approaches to understanding aggressive behavior in people.
The Biological Approach. Numerous biological structures and chemicals appear to be involved in aggression. One is the hypothalamus, a region of the brain. In response to certain stimuli, many animals show instinctive aggressive reactions. The hypothalamus appears to be involved in this inborn reaction pattern: electrical stimulation of part of the hypothalamus triggers stereotypical aggressive behaviors in many animals. In people, however, whose brains are more complex, other brain structures apparently moderate possible instincts.
According to paragraph 2, what evidence indicates that aggression in animals is related to the hypothalamus?
A. Some aggressive animal species have a highly developed hypothalamus.
B. Electrical stimulation of the hypothalamus results in aggression in animals.
C. Animals behaving aggressively show increased activity in the hypothalamus.
D. Animals who lack a hypothalamus display few aggressive tendencies.
