The answer would be “many animals die prematurely in zoos because they are exposed to infectious diseases.” The claim is stating that something bad is happening in zoos and this one is the only bad side effect in the choices.
Jack has a more appealing leadership because he campaigns that his tribe will have fun and hunt for pigs (which is appealing to the protein deprived children). Ralph and Piggy don't try to make the situation fun, they realise that they have things they need to do in order to survive and especially in order to be rescued. They build shelters, firewood, and take care of the little-uns. This is all very exhausting unappealing work for boys of their age who aren't all at the maturity Ralph, Piggy, Simon, and the twins seem to have. They would rather chant war calls and run around than to work and worry. (Haven't read this book in awhile but I hope this helps!)
The correct answer is to B. De-emphasize the subject.
Very often the subject can be completely omitted.
Burglars committed the crime
The crime was committed (by the burglars).
In the passive version, the subject is irrelevant.
