______ can be polluted from fertilizers and can harm organisms when it is heated and released into the environment.

______ can be polluted from fertilizers and can harm organisms when it is heated and released into the environment.

• A. Air
• B. Water
• C. Soil
• D. Rivers

Answer: (B)

Water is the medium that fits both parts of this idea. Fertilizers add nutrients like nitrates and phosphates that can run off into water bodies—streams, lakes, and rivers—where they fuel excessive plant growth (algal blooms). When these blooms die, they decompose and use up oxygen, harming aquatic life. At the same time, releasing water that has been heated (thermal pollution) raises the temperature of a body of water, which lowers the dissolved oxygen available to organisms and disrupts ecosystems. So water is the best fit because it explains both how fertilizer pollution occurs and why heated water released back into the environment can harm organisms. Air and soil don’t naturally connect both ideas in the same way, and while a river is a type of water, the statement refers to the broader medium rather than a specific body of water.

Water is the medium that fits both parts of this idea. Fertilizers add nutrients like nitrates and phosphates that can run off into water bodies—streams, lakes, and rivers—where they fuel excessive plant growth (algal blooms). When these blooms die, they decompose and use up oxygen, harming aquatic life. At the same time, releasing water that has been heated (thermal pollution) raises the temperature of a body of water, which lowers the dissolved oxygen available to organisms and disrupts ecosystems. So water is the best fit because it explains both how fertilizer pollution occurs and why heated water released back into the environment can harm organisms. Air and soil don’t naturally connect both ideas in the same way, and while a river is a type of water, the statement refers to the broader medium rather than a specific body of water.