Answer:
B
Explanation:
Is source of Lava all you are going to put in the second section? If it is, that eliminates both the first and last ones. Part 2 is always safe, no matter what comes next.
If it's a science report, part 2 is safe. I think I'd pick it. Dull but it directs the reader to a change.
-1 is the sum of 3+(-4) because you have to subtract the negative from the positive and then you will get -1.
The main idea of the passage.