Concept:Sedimentary cycles have their main reservoir in the earth’s crust and soil, not in the atmosphere.Explanation:Phosphorus does not occur as a gas in significant amounts in the atmosphere.Its main reservoirs are rocks and soil, where it exists as phosphate compounds.Because phosphorus is stored and cycled mainly on land and in water, it is considered an earthbound element.This makes the phosphorus cycle a sedimentary cycle rather than a gaseous cycle.Answer:B. is an earthbound element.