Surface water is naturally purified through several processes, and the options you provided highlight some of these. Here's a breakdown:
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Soil filters the water: True. When surface water percolates through soil, particles and impurities are often trapped, and biological processes in the soil can break down certain contaminants, effectively filtering the water.
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Evaporation leaves impurities behind: True. When water evaporates, it transforms into vapor, leaving behind impurities such as salts and other pollutants. This process can lead to the formation of cleaner water.
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Freezing water destroys impurities: This statement can be misleading. Freezing doesn't necessarily destroy impurities. While some contaminants might not freeze, others can be trapped in ice. However, some processes associated with freezing can lead to the separation of certain impurities as the ice forms, since some contaminants might remain in the liquid phase.
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Sediments precipitate out: True. As water flows, heavier particles and sediments can settle at the bottom, leading to the removal of some impurities from the water column.
Overall, the most accurate methods of natural purification from your options are soil filtration, evaporation, and sedimentation.