<span>A. response to a stimulus</span>
Basically all a vaccine is would be cells from the virus that is injected into you but the catch is the virus has been altered to prepare your immune system for what is to come if you catch the original virus so the correct answer would be C hope this is helpful for you.
Oceans cover 71% of the planet !
Pamela has Acquired Immunodeficiency syndrome (AIDS)
Acquired Immunodeficiency syndrome (AIDS) is a diseases that
breakdown the immune system in which the body is unable to fight off any form
infection that might attack the body. Thus, the infection that attack the body
when the immune system is weak can be refers to as opportunistic infections.