Ecosystem and Feeding Relationships Quiz For Kids, Lean about producers, consumers, decomposers, science activity for 4th, 5th And 6th Grade Kids. In this science test students will learn about an ecosystem through a diagram that shows the complex web of relationships organisms exhibit between on another and their environment. In an ecosystem, there are large predators like lions that feed on smaller animals and organisms as tiny as bacteria and fungi which decompose every living component of an ecosystem. Students will learn concepts related to ecosystems and how they function.-