Question

what is the main characteristic of autoimmune diseases? autoimmune diseases occur when the immune system mistakenly attacks the bodys cells. autoimmune diseases primarily affect the functioning of organs and systems. autoimmune diseases result from the bodys inability to identify external threats.

Explanation:

Autoimmune diseases are characterized by the immune system mistakenly attacking the body's own cells. This is the fundamental mechanism behind such diseases. The other options do not accurately describe the main characteristic.

Answer:

Autoimmune diseases occur when the immune system mistakenly attacks the body's cells.