Final answer:
Phosphorus is introduced into the environment through various mechanisms, but natural weathering of rocks is not a typical way.
Step-by-step explanation:
Phosphorus is introduced into the environment through various mechanisms, but one of the options listed is NOT a typical way it is introduced. Atmospheric deposition, agricultural runoff, and industrial discharge are all processes that contribute to the introduction of phosphorus into the environment. However, natural weathering of rocks is NOT a way phosphorus is typically introduced into the environment.