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The horizontal fraction bar was introduced by the Arabs.
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
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.
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.
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.