Living organisms interact with their environment through different ways e.g.: when we respire, we react with our atmosphere by exchanging gases with it. When particular organisms like fungi decompose the dead bodies of living beings then they interact with the soil and provide it with the necessary nutrients which are needed by plants, so these nutrients are recycled. So the interaction between the living organisms and their environment is so necessary for the recycling of nutrients & hence the existence of life on the planet Earth. These interactions are the condition for life on this planet. Many living beings interact with nonliving environment as well as with their living environment. For example lions feed on deers and their lives depend upon deers. But if the lion extincts then there would be no other factor to control the population of deers and the overcrowdness of deers will be dangerous for the plants. So all organism interact with each other directly or indirectly and form a network which we call as community or ecosystem. These communities also interact among each other and form a large community i.e. a biosphere. Every organism has its own importance in a ecosystem which can't be ignored.