Which of the following is the correct order of the three lines of defense against pathogens?
A) barriers that exclude pathogens → adaptive immunity → innate immunity
B) barriers that exclude pathogens → innate immunity → adaptive immunity
C) innate immunity → adaptive immunity → barriers that exclude pathogens
D) adaptive immunity → barriers that exclude pathogens → innate immunity
E) adaptive immunity → innate immunity → barriers that exclude pathogens

Question

Which of the following is the correct order of the three lines of defense against pathogens?​
A) ​barriers that exclude pathogens → adaptive immunity → innate immunity
B) ​barriers that exclude pathogens → innate immunity → adaptive immunity
C) ​innate immunity → adaptive immunity → barriers that exclude pathogens
D) ​adaptive immunity → barriers that exclude pathogens → innate immunity
E) ​adaptive immunity → innate immunity → barriers that exclude pathogens

Quizplus · Accepted Answer

The correct order of the three lines of defense against pathogens starts with physical and chemical barriers (such as skin and mucous membranes) that exclude pathogens. If these barriers are breached, the innate immune system provides a second line of defense, offering a non-specific response to pathogens. Finally, if these two lines of defense are insufficient, the adaptive immune system provides a third line of defense, targeting specific pathogens with a tailored response.

Which of the Following Is the Correct Order of the Three