Question

which body system produces proteins that help fight infections?
the digestive system
the immune system
the muscular system
the circulatory system

Explanation:

The immune system produces antibodies, which are proteins that recognize and neutralize pathogens to fight infections. The digestive system is for breaking down food, the muscular system for movement and support, and the circulatory system for transporting blood and substances.

Answer:

B. the immune system