The answer is C and D.
I hope this helps. Good luck!
Answer:
The flooding of half part of the forest have successful separate the population of frogs in that ecosystem into two different set of frogs. This is an example of allopatric speciation, that is, the population become separated as a result of geographical barrier. This separation will make the two set of frog population to become new species. On the long run, the two species may become unable to relate sexually.
Explanation:
B . Excessive commercial fishing
Reason: the other options are good things this is the only bad thing