The document describes the different levels in an ecosystem's food chain. Producers include plants and algae that produce their own food through photosynthesis. Consumers are divided into primary, secondary, and tertiary consumers depending on what they eat. Decomposers, such as fungi and bacteria, break down remains and waste, returning nutrients to the soil. Food chains connect different species based on predator-prey relationships, and food webs combine multiple interconnected food chains in an ecosystem.