Which of the following brain structures is associated with instinctive aggressive reactions in nonhumans?

A) amygdala
B) hippocampus
C) cerebellum
D) hypothalamus

The hypothalamus is a brain structure associated with instinctive aggressive reactions in nonhumans. It regulates the release of hormones and controls behaviors such as aggression, sexual behavior, and feeding. The amygdala is also involved in aggressive behavior, but it is more closely associated with fear and anxiety. The hippocampus is primarily involved in learning and memory, while the cerebellum is involved in balance and coordination.