Question

How can one organism help control the population of another organism? help me 

Answer 1

An organism can help control the population of other organisms by eating it or killing it. For example humans control the population of deer by hunting them.

Answer 2

I think it's because one animal can change one thing in the ecosystem (how all living things interact with each other) and that triggers a chain reaction which leads to the other animal being helped e.g. in Yellowstone national park, the deer had overpopulated and there was barely any vegetation. This also led to other animals not thriving and the river changed course. But when they introduced wolves, they brought down the numbers of deer, which led to the vegetation growing back, which gave other animals a chance to thrive and the river went back to normal. Hope this solves your problem!