Final answer:
The amygdala is the part of the brain responsible for regulating emotions, particularly fear and anxiety, and is a key structure within the limbic system.
Step-by-step explanation:
The part of the brain responsible for regulating emotions is the amygdala. The amygdala, located within the temporal lobe, is part of the limbic system and is involved in processing emotions such as fear and anxiety, as well as recognizing fearful faces. It has connections with various sensory areas of the brain, playing a critical role in classical conditioning and attaching emotional value to learning processes and memory.