Unlike the carbon cycle, the phosphorous cycle does not involve
a. geological processes.
b. chemical and physical processes.
c. human activity.
d. biological processes.

The right answer is c. human activity. Phosphorus cycle takes place even without human involvement but it can still affect or cause major changes in this nutrient cycle. Humans use fertilizers and raise livestock (hogs). Waste from livestock and fertilizers are high in phosphate that gets into the soil and bodies of water through drainage and run-off.