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beaver

(Encyclopedia)beaver, either of two large aquatic rodents, Castor fiber and Castor canadensis, known for their engineering feats. They were once widespread in N and central Eurasia except E Siberia, and in North Am...

dentistry

(Encyclopedia)dentistry, treatment and care of the teeth and associated oral structures. Dentistry is mainly concerned with tooth decay, disease of the supporting structures, such as the gums, and faulty positionin...

wood

(Encyclopedia)CE5 Wood A. Cross section of a woody stem B. Enlarged view, showing xylem, phloem, and cambium wood, botanically, the xylem tissue that forms the bulk of the stem of a woody plant. Xylem conducts ...

nutrition

(Encyclopedia)nutrition, study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Nutrition is achieved in vario...

refraction

(Encyclopedia)refraction, in physics, deflection of a wave on passing obliquely from one transparent medium into a second medium in which its speed is different, as the passage of a light ray from air into glass. O...

mitosis

(Encyclopedia)CE5 Mitosis in a body cell of an animal mitosis mītōˈsĭs, mĭ– [key], process of nuclear division in a living cell by which the carriers of hereditary information, or the chromosomes, are ex...

broadcasting

(Encyclopedia)broadcasting, transmission, usually using radio frequencies, of sound or images to a large number of radio or television receivers. In the United States the first regularly scheduled radio broadcasts ...

mirror

(Encyclopedia)mirror, in optics, a reflecting surface that forms an image of an object when light rays coming from that object fall upon it (see reflection). Usually mirrors are made of plate glass, one side of whi...

light

(Encyclopedia)light, visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range ...

pulse, in botany

(Encyclopedia)CE5 Sweet pea, Lathyrus odoratus, a member of the pulse family pulse, in botany, common name for members of the Fabaceae (Leguminosae), a large plant family, called also the pea, or legume, family...