Question

according to the text, eutrophication primarily results from:
agricultural runoff
climate change
overfishing
natural cycles

Explanation:

Eutrophication is mainly caused by an excess of nutrients entering water - bodies. Agricultural runoff often contains fertilizers rich in nitrogen and phosphorus which can cause eutrophication. Climate change may have secondary or indirect effects on eutrophication. Overfishing and natural cycles are not the primary causes of eutrophication.

Answer:

agricultural runoff