Which of the following describes how infectious agents in the environment would most likely affect one’s personal health? a. exposure would first cause a cell-mediated immune response from the body. b. infectious agents would trigger nonspecific external defenses such as sweat, saliva, and mucus. c. exposure would weaken the body’s immune system and leave it unable to fight future infections. d. infectious agents would invade the body and leave it unable to produce antibodies.