1. Which is not a function of the skeletal system? a. It produces blood. b. It supports the body. c. It protects internal organs d. It protects you from disease-causing microorganisms. 2. Which system in the human body works together with the circulatory system to ensure that the right gases are circulated around the body? a digestive system c. respiratory system b. muscular system d. skeletal system 3. What blood cells transport oxygen and carbon dioxide? a White blood cells c. platelets b. Red blood cells d. plasma