Human Anatomy and Physiology Help

I'm doing my homework, and I'm not sure how to answer this question...
What is the relationship between structure & function? Give some examples from molecular, cellular,
tissue, organ, system, & organismal levels

Things are structured so that they can function at their best. Your body has two legs so you can walk upright. Your brain is divided into areas of specialization so you can think complex thoughts. Your white blood cells are shaped so that they can easily fight infection. Etc. Another way you'll see this stated is "form and function..." Good luck with your homework!