What do the Kidneys Do?
 

The kidneys remove undesireable substances from blood plasma (the liquid part).
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What undesireable substances?	1. toxins                                     2. metabolism wastes 3. excess ingested water   4. excess mineral salts
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How much do they filter each day?.	about 150 quarts of blood plasma
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The kidneys also regulate the acidity of the blood.
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How do they do that?	by excreting alkaline salts