My answer would be:
the destruction wrought when ambition goes unchecked by moral constraints—finds its most powerful expression in the play's two main characters.
I don't think a correction is necessary. Both parts of the sentence are already in the present tense. Plus, the use of "us" in the beginning of the sentence indicates a personal attachment.
I believe it would be A. Violence can be uncontrollable.
Answer:
1. I don't agree with this statement. Sometimes panic can determine life or death. But so can too much panic.
2. I don't agree with this statement. 300 people, and counting, have died while trying to reach the top. It's cold and dangerous.
3. I agree with this statement. Deserts are very hot. It's hard to find shelter, food, and water as well.
12 is A
13 is B
14 is B
15 is C