Humans have how many generalized lines of defense against disease or infection?

Question

Humans have how many generalized lines of defense against disease or infection?​

Quizplus · Accepted Answer

Humans have three generalized lines of defense against disease or infection: physical and chemical barriers, innate immune system, and adaptive immune system. Option A and Option C are incorrect because humans do not have only two or four generalized lines of defense against disease or infection. Option D is incorrect because, despite some sources suggesting there could be a fifth line of defense, it is not yet widely accepted in the scientific community.

Humans Have How Many Generalized Lines of Defense Against Disease