Food chain

 A food chain is a linear sequence of links starting from species that are called producers in the web and ends at species that are called decomposers (or Apex Predators) in the web. A food chain also shows how the organisms are related with each other by the food they eat. A food chain differs from a food web. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the chain.