The difference is the following: Fission is when a heavy nucleus is very unstable and is splitted into two lighter nuclei. Fusion is in a sense the contrary process: two light nuclei combine and release more energy
The awnser your looking for would be B: It's Population decreases. Because if a species is unable to adapt to a changing environment the species would either have to move away or they could die in that location.
Here you go I just googled it
Answer:
A compound is a substance which contains two or more elements chemically combined together.
A compound is formed as a result of a chemical change.
Explanation: