AP BIOLOGY

Detailed explanation-1: -Internal stimuli are internal factors that cause an organism to respond in order to maintain homeostasis. In animals, there are nerve receptors inside the body that will pick up on changes that occur, such as oxygen and carbon dioxide levels, blood sugar levels, water levels, blood pH, and core body temperature.

Detailed explanation-2: -A stimulus is anything that can trigger a physical or behavioral change. The plural of stimulus is stimuli. Stimuli can be external or internal. An example of external stimuli is your body responding to a medicine. An example of internal stimuli is your vital signs changing due to a change in the body.

Detailed explanation-3: -Animals may respond to environmental stimuli through behaviors that include hibernation, migration, defense, and courtship. As a result of cold, winter weather (stimulus) some animals will hibernate.

Detailed explanation-4: -Internal stimuli are changes inside an organism. They include hunger, thirst, and pain. If you feel hungry and look for food, you are responding to an internal stimulus-hunger. The feeling of thirst that causes you to look for water is another internal stimulus.