|
|
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
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.
Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
People with high total cholesterol have about two times the risk for heart disease as people with ideal levels.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.