11) Humans are warm-blooded organisms that maintain a constant body temperature around 37°C. The diagram shows the changes that take place to keep human body temperature constant. Brian claims that only the muscular system is involved when body temperature drops. He says that shivering occurs when the body’s muscles contract rapidly, producing heat, and that this muscle action keeps the body warm. Identify two pieces of evidence from the diagram that either support or refute Brian’s claim.