What natural system purifies water? A-carbon filtration
B-sewage treatment plant
C-particles precipitate out in oceans and lakes
D- the water cycle

The water cycle

Explanation:

When water is evaporated whatever dirt or salt particles were in it do not get evaporated with it. So when it falls back to earth (as rain, snow, hail, ect.) it is technically pure, until something is added to it.

The water cycle just had it on a quiz

Explanation:

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