A consumer is something or someone who eats something or someone. It consumes that item or being. One example of a consumer is a person. People consume food like meat, vegetables, and fruits. Another example of a consumer is a lion. Lions consume their prey, which usually consists of a wide range of mammals in their natural habitat.
The consumer is important to the economic system because if a lion didn't consume any mammals then that mammals population would increase significantly, making them overpopulated. The consumer eats their prey to stay alive, and if they didn't consume their prey, the prey wouldn't die off as fast. If a lion didn't eat a zebra, the zebra population would skyrocket, and the zebra's would have to eat much more grass or leaves and drink much more water, leaving those resources decreasing.