Every species has a role to play in the ecosystem. Explain the statement.

 An elaborated answer (not copy paste from some other web pages)

Then which kind of answer do you want? How are you still confused?

 i am not confused, i want to know how to write answer for this question if it comes for 3 or 4 marks.

Okay, it's like this:

We know that all species are interdependent on each other and together support the food chain, So it is easy to say that any disturbance in this chain can be very hazardous to an ecosystem. This is exactly what man has been doing in the last two centuries or so(hope you won't ask how). The extinction of any species in an ecosystem can seriously damage it and is very dangerous to other species as well. If you want a longer answer, I am helpless.

Thanks for your help. And I got a better answer than this. And I dont think your answer is exactly an answer to my question.

Sorry to know that yo think so.