Which of the following contributes to nutrient pollution in lakes?

Nutrient pollution in lakes is primarily attributed to the introduction of excess nutrients, such as nitrogen and phosphorus, into the aquatic ecosystem. This phenomenon often leads to harmful algal blooms, decreased oxygen levels, and overall degradation of water quality.

Industrial effluent can contribute nutrients through the discharge of wastewater that contains fertilizers or nutrient compounds used in various manufacturing processes. Fertilized lawns contribute when rainwater runs off, carrying nitrogen and phosphorus from the fertilizers into nearby waterways and lakes. Agricultural runoff is another significant source, as fertilizers used in agriculture can wash into lakes during rainfall or irrigation.

Since both industrial activities, residential landscaping, and agricultural practices can significantly add to the nutrient load in lakes, all of these sources collectively contribute to nutrient pollution. Therefore, recognizing that each of these sources plays a role illustrates why the most comprehensive answer encompasses all of these options.