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.

a .

Explanation:

a group of cells and organs that protect the body from disease

B

Explanation:The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. ... Even simple unicellular organisms such as bacteria possess a rudimentary immune system in the form of enzymes that protect against bacteriophage infections.

stridor can't collapse a lung.

very