a series of living creatures in which each type of creature feeds on the one below it in the series

a system or structure in which the people or organizations that are part of it are seen as having different levels of importance, success, etc.

<i>These guys are at the top of the food chain when it comes to earnings.</i>

the series of stages that food passes along as it goes from being grown or produced to being sold and then eaten 

<i>They are focused on ensuring that contaminated crops do not enter the food chain.</i>

LEARNit Dictionary