Final answer:
The cough reflex is a nonspecific, secondary line of defense in the immune system.
Step-by-step explanation:
The cough reflex is a nonspecific, secondary line of defense in the immune system.
The immune system has two lines of defense: the first line of defense, which includes physical barriers like the skin and mucous membranes, and the second line of defense, which involves nonspecific immune responses that help fight off pathogens that have managed to enter the body.
The cough reflex is part of the second line of defense. It helps remove foreign particles, such as pathogens, from the respiratory system by forcefully expelling them through a cough.