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The most dangerous mercury compound, dimethyl mercury, is so toxic that even a few microliters spilled on the skin can cause death. Mercury has been shown to accumulate in higher amounts in the following types of fish than other types: swordfish, shark, mackerel, tilefish, crab, and tuna.
People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.