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After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
There are more nerve cells in one human brain than there are stars in the Milky Way.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
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