Concept:A sedimentary cycle is one whose main reservoir is the Earth's crust and soil, not the atmosphere.
Explanation:The phosphorus cycle is described as sedimentary because phosphorus is an earth-bound element.
Unlike carbon, oxygen, and nitrogen, phosphorus does not have a significant gaseous phase in the atmosphere.
The atmosphere is not a reservoir for phosphorus.
Also, microorganisms do not fix phosphorus from the air as they fix nitrogen.
Phosphorus enters the biosphere almost entirely through plant roots absorbing it from the soil.
The soil phosphorus itself comes from the weathering of rocks.
So the movement of phosphorus is mainly between the Earth's crust, soil, water, and living organisms.
This makes the phosphorus cycle sedimentary rather than gaseous.
Answer:C. is an earth bound element