Which of the following pollutants can lead to hypoxia in aquatic environments?

Nutrients, particularly nitrogen and phosphorus, are key contributors to hypoxia in aquatic environments. When these nutrients are present in excessive amounts, often due to agricultural runoff, they promote a phenomenon known as eutrophication. This process leads to algal blooms, which can deplete oxygen levels in the water as the algae die and decompose. The decomposition process consumes large amounts of dissolved oxygen, leading to hypoxic conditions where oxygen levels are insufficient to support most aquatic life. As a result, the correct answer highlights how nutrient pollution can dramatically impact the health of aquatic ecosystems by reducing oxygen availability, ultimately harming fish and other organisms dependent on adequate oxygen levels.