During a routine check-up, a medical assistant is asked by a patient about the body's first line of defense against infection. Which of the following should the medical assistant include in their explanation?
Stomach acid destroys pathogens that are ingested with food and drink.
Antibodies produced by B cells in response to an infection neutralize pathogens.
Intact skin acts as a physical barrier to prevent the entry of pathogens.
Mucus in the respiratory tract traps pathogens as they are inhaled.