Pick a body function that requires at least two different organ systems to perform. The function can be involuntary or voluntary. Design a model that shows how these systems work together. You may want to localize the function to a specific body part. For example, running involves many muscles and bones, which may make it difficult to model. However, you can focus on a specific motion for running, such as bending the knee joint. In a paragraph, explain why it requires at least two body systems to perform the function you selected.