Question

use your understanding of the phosphorus cycle to answer the questions provided. phosphorus cycles between living things and the \boxed{}.

Explanation:

In the phosphorus cycle, phosphorus moves between living organisms and the non - living environment, specifically the soil (or more broadly, the geosphere/earth's crust, as phosphorus is found in rocks, soil, etc.). The main non - living reservoir for phosphorus is the soil (and rocks from which it weathers into soil).

Answer:

soil (or geosphere/earth's crust, but "soil" is a common and direct answer here)