Question

the phosphorus cycle differs from the biogeochemical cycles in that
it does not have an atmospheric reservoir.
it does not have an oceanic reservoir.
there is no assimilation of phosphorus.
there is no decomposition of phosphorus.

Explanation:

To solve this, we analyze the phosphorus cycle. Biogeochemical cycles like carbon, nitrogen have atmospheric reservoirs. The phosphorus cycle's main reservoirs are rocks, soil, water (oceanic reservoir exists as phosphate in oceans), and organisms assimilate (take in) and decompose phosphorus. So the key difference is no atmospheric reservoir.

Answer:

A. It does not have an atmospheric reservoir.