Question

what is the immune system? a the group of cells and organs that protect the body from disease. b a group of cells that undergoes apoptosis to protect the body. c a group of organelles that digest particles that invade the cells. d the group of cells and organs that turn food into energy for the body.

Explanation:

The immune system is a complex network of cells and organs that defend the body against pathogens and diseases. Option A correctly defines it as the group of cells and organs that protect the body from disease. Option B is about apoptosis which is not the main function - based definition of the immune system. Option C describes the function of some organelles like lysosomes rather than the immune - system. Option D describes the function of the digestive system.

Answer:

A. The group of cells and organs that protect the body from disease.