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Did you know?

The human body's pharmacokinetics are quite varied. Our hair holds onto drugs longer than our urine, blood, or saliva. For example, alcohol can be detected in the hair for up to 90 days after it was consumed. The same is true for marijuana, cocaine, ecstasy, heroin, methamphetamine, and nicotine.

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There are approximately 3 million unintended pregnancies in the United States each year.

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Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.

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A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.

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In the ancient and medieval periods, dysentery killed about ? of all babies before they reach 12 months of age. The disease was transferred through contaminated drinking water, because there was no way to adequately dispose of sewage, which contaminated the water.

Human hand and wrist anatomy Human hand and wrist anatomy
Human hemoglobin variants Human hemoglobin variants
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Human arrival and the extent of the recent extinction wave Human arrival and the extent of the recent extinction wave
Some human traits controlled by a single gene Some human traits controlled by a single gene
Lobes of the brain, with primary receiving and integrating centers of the human cerebral cortex. Lobes of the brain, with primary receiving and integrating centers of the human cerebral cortex.
Video: Cataract

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