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Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.
IgA antibodies protect body surfaces exposed to outside foreign substances. IgG antibodies are found in all body fluids. IgM antibodies are the first type of antibody made in response to an infection. IgE antibody levels are often high in people with allergies. IgD antibodies are found in tissues lining the abdomen and chest.
More than 50% of American adults have oral herpes, which is commonly known as "cold sores" or "fever blisters." The herpes virus can be active on the skin surface without showing any signs or causing any symptoms.
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
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.