This would be cancer
Cancer are just cells multiplying at a alarming rate that can kill healthy cells and weaken your immune system.
Syphilis is transmitted through sexual actions through small cuts, for malaria, it would have to be through mixing of blood from a contaminated source to a uncontaminated source.
Answer:
The answer is "Cell Membrane".
Answer:
Well, sometimes you use the process of elimination in some areas.
Explanation:
For example,
You don't have common sense in math class, but you can determine how to divide and multiply an equation. Sometimes you don't have to be "AP Smart", and you can still have all A's.
Or you could just research the answers :)