HURRY
In order to fight invaders, an immune response
A can recognize substances that are not a part of the body.
B releases a substance that acts as a pathogen.
C is activated by cancers.
D can recognize viruses in the body, such as E. coli.
I think it’s A because it needs to recognize substances that are not part of the body to fight them it will not just fight your regular red blood cells so there for it has to be A
