Question

Which describes a way in which phosphorus may enter into the phosphorus cycle?
Earthquakes release phosphorus.
Phosphorus is carried in the rain that was evaporated from lakes.
Human use of fertilizers release phosphorus into the groundwater.

Answer 1

Human use of fertilizers release phosphorus into the groundwater.

Explanation: Phosphorus mainly enters the cycle by weathering of phosphate-bearing rocks and by human inputs (fertilizer runoff/leaching into soils and groundwater, sewage). Phosphorus does not have a gaseous phase, so it is not carried in evaporated water and returned in rain. While tectonic activity can expose phosphate rocks to weathering, earthquakes themselves are not a direct common source.