Answer:
C. The immune system damages a person's own cells, tissues, and organs while fighting off invading pathogens.
When the immune system is activated to fight off an invading pathogen, it can sometimes mistakenly attack the body's own cells, tissues, and organs. This can lead to symptoms of disease and inflammation. For example, in autoimmune diseases, the immune system mistakenly attacks and damages healthy cells and tissues in the body, leading to symptoms such as pain, fatigue, and organ damage. In some cases, the immune system may also overreact to a mild invader, such as pollen, leading to allergy symptoms.