Question

1. which human activity contributes most to excess phosphorus in aquatic ecosystems? fossil fuel combustion use of synthetic fertilizers overharvesting forests industrial emissions

Explanation:

Synthetic fertilizers are rich in phosphorus. Run - off from agricultural lands where these fertilizers are used can carry excess phosphorus into aquatic ecosystems. Fossil fuel combustion mainly releases carbon - based pollutants and other trace elements, not significant amounts of phosphorus. Overharvesting forests affects soil erosion and habitat but not directly phosphorus input to water bodies. Industrial emissions typically have heavy metals, sulfur, and other pollutants rather than large amounts of phosphorus.

Answer:

Use of synthetic fertilizers