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Protista

(Encyclopedia)Protista prōˌtŏktĭsˈtə [key], in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms. Pro...

frostweed

(Encyclopedia)frostweed or frostwort, North American woodland flowers (Helianthemum canadense and sometimes other related species) of the family Cistaceae (rockrose family). In cold weather, crystals of ice shoot f...

mare's-tail

(Encyclopedia)mare's-tail, any plant of the genus Hippuris, perennial, submerged aquatic herbs of temperate and frigid regions. Mare's-tails have an erect stem bearing whorls of small leaves, so they resemble some ...

vascular bundle

(Encyclopedia)vascular bundle, in botany, a strand of conducting tissue extending lengthwise through the stems and roots of higher plants, including the ferns, fern allies, gymnosperms, and angiosperms. The vascula...

acquired characteristics

(Encyclopedia)acquired characteristics, modifications produced in an individual plant or animal as a result of mutilation, disease, use and disuse, or any distinctly environmental influence. Some examples are docki...

Semenza, Gregg Leonard

(Encyclopedia)Semenza, Gregg Leonard, 1956–, American oncologist and molecular biologist, b. New York City, Ph.D. Univ. of Pennsylvania, 1984. Semenza has spent his entire career at the Johns Hopkins School of Me...

erythroblastosis fetalis

(Encyclopedia)erythroblastosis fetalis ərĭthˌrəblăstōˈsĭs [key], hemolytic disease of a newborn infant caused by blood group incompatibility between mother and child. Although the Rh factor is responsible f...

virology

(Encyclopedia)virology, study of viruses and their role in disease. Many viruses, such as animal RNA viruses and viruses that infect bacteria, or bacteriophages, have become useful laboratory tools in genetic studi...

sapwood

(Encyclopedia)sapwood, relatively thin, youngest, outer part of the woody stem of a tree, the part that conducts water and dissolved materials. In the cross section of a tree, the sapwood is recognizable by its tex...

coma, in medicine

(Encyclopedia)coma, in medicine, deep state of unconsciousness from which a person cannot be aroused even by painful stimuli. The patient cannot speak and does not respond to command. Coma is the result of damage t...