What is the primary mechanism by which vaccines protect individuals from infectious diseases?

The correct answer to the question "What is the primary mechanism by which vaccines protect individuals from infectious diseases?" is Option C: They stimulate the immune system to produce protective antibodies and memory cells..

The other options — A) They directly kill the disease-causing pathogens in the body., B) They introduce antibodies that immediately fight off infection., D) They create a physical barrier against pathogen entry. — are incorrect for this Everyday Science question. As explained above: Vaccines work by exposing the immune system to a weakened, inactivated, or partial form of a pathogen, prompting the body to develop an immune response (antibodies and memory cells) without causing t…