Rats that have a damaged __________will show no fear when placed next to a cat.

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

The amygdala is a key part of the brain's fear response system, and damage to this area has been linked to diminished fear responses in animals. Therefore, rats with damaged amygdalas would be expected to show no fear when placed next to a predator like a cat. The other options listed (hippocampus, hypothalamus, and fornix) are not directly involved in processing fear and are less likely to have a direct impact on fear-related behaviors.