Answer:
John: he has naturally acquired active immunity to chicken pox from previous exposure.
Explanation:
Your body naturally has some immunity to things that aren't you, but when you get sick with a specific pathogen, your body begins to make antibodies that specifically recognize that pathogen. Each antibody only recognizes one pathogen, and it floats around waiting to find it again so it can tell your body to kill it before you get sick again. This is why we become immune to chicken pox; after the first time you beat it, your body has the labeled antibodies and it can quickly destroy the pathogen before you get sick again.
I'm pretty sure its A bit of not its D, sorry but its kinda hard to tell :/
Answer:
overly large cells have a lower surface area:volume ratio. a large surface area is needed to obtain nutrients, dispose of substances, and for diffusion to occur. A giant cell would not be able to accomplish these tasks effeciently enough, and would eventually die
The virus that you want to grow immune to is injected into your body. This helps your body create antibodies to fight of the virus.
Conditioned stimulus
Classical conditioning is a learning procedure in which a biologically potent stimulus paired with previously neutral stimulus. This pairing will cause a response that can be the same as the potent stimulus. This is done repeatedly for an organism to elicit a conditioned response to the previously neutral stimulus that was paired to the active stimulus. The dog salivates due to the idea that food is related to the sound of the bell.