Which statement best describes the phosphorus cycle?

• A. The movement of phosphorus atoms from rocks through the biosphere and hydrosphere and back to rocks.
• B. The cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment.
• C. The evaporation of phosphorus from soil to air and back.
• D. The dissolution of phosphorus in water without organisms.

Answer: (A)

Phosphorus cycles by weathering rocks to release phosphate, which enters soils and waters, is taken up by organisms, and returns to the environment as organic matter or minerals. Over long timescales, that material can be deposited and transformed back into rock, completing the cycle. The statement that best describes this emphasizes moving from rocks through the living world and into water bodies, then back to rocks, capturing both the rock source and the geological return. Evaporation isn’t a meaningful part of the phosphorus cycle, and while phosphorus changes forms, the key feature is its movement between rock, living organisms, and the environment, with geological processes restoring rocks over time.