Which body system produces proteins that fight infections?

Answer and Explanation:

The Immune System. It comprises the white blood cells, lymphatic system, etc. The immune response is the production of antibodies in response to antigens present in pathogens and other foreign matter.

The leukocytes are formed in the bone marrow of long bones and lymph nodes. Their function is to protect the body from invasion of foreign material like bacteria and viruses( pathogens). They help fight against infections by engulfing and digesting pathogens and production of antibodies which are proteins that bind to pathogens. Their number increases greatly during infections.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.

i think its white blood cells

i hope this