9. Explain why there is a need of a variety of animals and plants in a forest.
All organisms residing at different levels of the food chain have some role or the other to play required for a balanced ecosystem. For example, plants and grass serve as food for the herbivores which serve as food for the carnivores and when these herbivores and carnivores die their dead bodies are decomposed by microorganisms and insects living in the soil and once these dead bodies are decomposed this enriches the soil which is essential for the plants. Hence, there is a need for a variety of animals and plants in a forest.