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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.
In most cases, kidneys can recover from almost complete loss of function, such as in acute kidney (renal) failure.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
Illicit drug use costs the United States approximately $181 billion every year.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.