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There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
Persons who overdose with cardiac glycosides have a better chance of overall survival if they can survive the first 24 hours after the overdose.
There are more nerve cells in one human brain than there are stars in the Milky Way.
The familiar sounds of your heart are made by the heart's valves as they open and close.
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