Because migration and and other seasonal movements can affect the possibility of finding a mate, stresses, that could affect offspring survival(can vary with season), and also availability of thing that are available for the offspring.
I’m almost 100% sure it’s D, because environmental factors can induce a mutation. A mutation can be beneficial but it can also be harmful, so it’s neither B or C, and it can’t be A, because mutations can come from natural selection as well. So it’s D.
Ecosystem is a living system, where living organisms interacts with their environment and among each other.
Due to some hazardous processes like, Global warming, Green-house effect, increasing pollution, ecosystem is degrading.
We live in our Ecosystem, if it will get destroyed, our existence would be impossible. So, in order to save ourselves, we need to save it.
That's why biologists, concerned about ecosystem disruption
Hope this helps!
