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: -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-3: -All but the simplest animals receive a stimulus-light, sound, taste, touch, or smell-through special cells called receptors, located in many places on or in the body. For example, fish have hairlike organs over much of their body, sometimes even on the tail.

Detailed explanation-4: -Instinct, imprinting, conditioning, and imitation are the four types of animal behavior.