Answer:
The Answer is likely D, none of the above because all of these would cause damage in any area, however, climate change is what deals the most damage to tropics due to the fact that the already hot tropical climate is getting even hotter, which can cause rivers and what not to dry out, whereas though climate change is a big problem around the world, it is least apparent in the southern hemisphere, and not nearly as apparent in the northern hemisphere when you compare it to research in the equatorial region.
(Please note that this answer is more of a matter of my own opinion than anything, and under most circumstances, none of the above would be wrong. Please do not hold it against me if this answer is wrong. If it is wrong, then the answer would probably be A)
If it has valves then it is a vein.
The following of what? It sounds like there is more than one answer.
