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root, in botany

(Encyclopedia)CE5 Longitudinal cross section of a root root, in botany, the descending axis of a plant, as contrasted with the stem, the ascending axis. In most plants the root is underground, but in epiphytes ...

umbilical cord

(Encyclopedia)umbilical cord ŭmbĭlˈĭkəl [key], cordlike structure about 22 in. (56 cm) long in the pregnant human female, extending from the abdominal wall of the fetus to the placenta. Its chief function is t...

cambium

(Encyclopedia)cambium kămˈbēəm [key], thin layer of generative tissue lying between the bark and the wood of a stem, most active in woody plants. The cambium produces new layers of phloem on the outside and of ...

death

(Encyclopedia)death, cessation of all life (metabolic) processes. Death may involve the organism as a whole (somatic death) or may be confined to cells and tissues within the organism. Causes of death in human bein...

clone

(Encyclopedia)clone, group of organisms, all of which are descended from a single individual through asexual reproduction, as in a pure cell culture of bacteria. Except for changes in the hereditary material that c...

cerebellum

(Encyclopedia)cerebellum sĕrˌəbĕlˈəm [key], portion of the brain that coordinates movements of voluntary (skeletal) muscles. It contains about half of the brain's neurons, but these particular nerve cells are...

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 ...

Wilmut, Sir Ian

(Encyclopedia)Wilmut, Sir Ian, 1944– British embryologist, b. Warwickshire, England, Ph.D. Cambridge, 1971. While doing postdoctoral research at Cambridge, he was part of the team that produced Frostie, the first...

thallophyte

(Encyclopedia)thallophyte, common name for members of the Thallophyta (or Thallobionta), a taxonomic group in some archaic classification systems that comprised algae, fungi, and lichens. The thallophytes were cons...

blood

(Encyclopedia)blood, fluid pumped by the heart that circulates throughout the body via the arteries, veins, and capillaries (see circulatory system; heart). An adult male of average size normally has about 6 quarts...