As joe walks to his car late at night, he hears footsteps behind him. feeling afraid, joe grips his keys and quickens his pace. it is likely that joe's has been activated select one:

As Joe walks to his car late at night, he hears footsteps behind him. Feeling afraid, Joe grips his keys and quickens his pace. It is likely that Joe's amygdala has been activated.

Explanation:

The amygdala is almond-shape mass of grey matter located inside each hemisphere of the brain that is involved with experimenting emotions. This is the section of the brain that is responsible for detecting fear and activating the emergency systems. Fear is a needed emotion, as it helps us to have self-preservation. When in a situation that can potentially harm us, our brain sends the message that we should protect ourselves from an external threat, in the form of fear. The amygdala is the responsible for activating different emotions in us, such as fear, anger, and sadness. When Joe hears footsteps behind him, while he is walking alone late at night, his amygdala sent him the message that he should protect himself in the form of fear, so that he could act on it.