Материалы по тегу «reverse osmosis»
More than 2 billion people on the planet do not have access to clean drinking water. From 5 to 8 million people a year die after consuming low-quality water and the number of those who fall ill amounts to half a billion
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What saints did the conquistadors pray to and why did they decide to conquer Mexico? What was the ethnic, regional, and age composition of the Conquista?