Explain how it is possible for organisms to play more than role an why it is important

The Food-chain.

Explanation:

For example, animals at the top of the food-chain, in their ecosystem, balance the population. The organisms at the bottom are the producers. Herbivores usually eat the producers which are multiple types of plants. Omnivores and herbivores are prey for the carnivores, but they are also predators to the herbivores. That's all I could really think of... :)