human
Question: Many fertilizers contain organic materials that are helpful to an orchard but have a different effect when rain causes them to run off into a freshwater ecosystem. How does the addition of organic waste from fertilizers most commonly affect freshwater ecosystems?

Choices:
A) increasing biodiversity
B) increasing water clarity
C) decreasing algae blooms
D) decreasing oxygen levels
gpt
The correct answer is 3: decreasing oxygen levels.