Example: An everyday activity is running.
Explanation: When you run, your respiratory system changes your breathing speed rapidly and drastically. Your lungs work harder to store oxygen you need to keep running with your muscles. With the respiratory system supporting your muscles, this allows the muscular system, which in this case are your leg muscles, to effectively run smoothly. (Sorry if this may not be the best answer, but this was what I first thought of. I hope it helped though!)