1. Digestive System: This system breaks down food into smaller molecules that can be absorbed by the body. This process releases energy from the food.
2. Respiratory System: This system takes in oxygen, which is essential for cellular respiration, the process where energy is extracted from food. It also removes carbon dioxide, a waste product of this process.
3. Circulatory System: This system transports the digested food molecules and oxygen throughout the body to reach cells that need energy. It also carries away waste products like carbon dioxide.
These three systems work together in a complex interplay to ensure that an animal has the energy it needs to survive and function.
