Dead zones are primarily caused by excess phosphorus and nitrogen entering ecosystems, leading to oxygen depletion and organism death.
Dead zones can be caused by excess phosphorus and nitrogen entering an ecosystem, leading to excessive algae growth. This growth depletes oxygen, leading to the death of aquatic organisms. Excess usage of fossil fuels does not directly cause dead zones, it's primarily the nutrient runoff that triggers them.
https://brainly.com/question/29018225