Answer:
The skeletal system produces blood cells.
Explanation:
Inside of the bones is the red bone marrow, among other things. The red bone marrow is also called hemopoietic tissue because it is where red (RBC) and white (WBC) blood cells are created. These cells are needed by the circulatory system since the RBCs transport molecules around the body and the WBCs protect the body from foreign agents. The RBCs also help the respiratory system since they carry oxygen and carbon dioxide. The WBCs are very important in the respiratory system as well since many pathogens will try entering the body through the lungs so they need protection.
