Holly takes night classes at the local community college. After her lecture, she walks alone to her car and suddenly hears several dozen screeching birds fly away from the tree she is walking under....

Holly takes night classes at the local community college. After
her lecture, she walks alone to her car and suddenly hears
several dozen screeching birds fly away from the tree she is
walking under. Holly immediately feels her heart pounding
and notices that her breathing rate has increased. Minutes later,
she still feels tense and “on edge.” What happened internally
to cause Holly’s initial response? Why did Holly still feel tense
minutes later?