The children in a middle school classroom are all exposed to chicken pox one week. Among these students are John, who had chicken pox when he was much younger, and Sara, who has never had chicken pox. Which student do you expect would be less likely to become ill with chicken pox following this exposure and why? (5 points) John: he has naturally acquired active immunity to chicken pox from his previous exposure. Sara: she has naturally acquired passive immunity to chicken pox from exposure to other students. John: the pathogens that cause chicken pox will no longer be able to enter his body. Sara: since she has not suffered from chicken pox, her immune system is probably stronger than Johns.

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.

John: he has naturally acquired active immunity to chicken pox from his previous exposure.

Explanation:

Ok, I know this is incredibly late and doesn't matter anymore, but I just wanna say that the person before me was correct. I just took the test and this was the correct answer.  

cancer   is   essentially   uncontrolled   mitosis   of specialized cells

that is wrong, its not thymus.