> The guys had tried each design available to make a pincer robot. You can find dozens of species populating each sea bottom from beaches to abyss and each fres

> The guys had tried each design available to make a pincer robot. You can find dozens of species populating each sea bottom from beaches to abyss and each freshwater body of water or marsh. This is a linguistic observation and completely beside the point, but there's an interesting difference between each and every: each implicitly involves a set of specific things, things individually identifiable in some context. If you say "each person has two parents" the hearer will assume you're already talking about some set of individuals, the ones in the room, say. If you say "every person has two parents" they will think you are making a generalization about people, including hypothetical people who have not been born, ancient people who left no trace in history, and so forth.