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political science

(Encyclopedia)political science, the study of government and political processes, institutions, and behavior. Government and politics have been studied and commented on since the time of the ancient Greeks. However...

steroids

(Encyclopedia)CE5 Two examples of steroids steroids, class of lipids having a particular molecular ring structure called the cyclopentanoperhydro-phenanthrene ring system. Steroids differ from one another in th...

spiritual

(Encyclopedia)spiritual, a religious folk song of American origin, particularly associated with African-American Protestants of the southern United States. The African-American spiritual, characterized by syncopati...

wall

(Encyclopedia)wall, in architecture, protective, enclosing, or dividing vertical structure. Its thickness is determined by the material, height, and stress. It may be of studding and lath, either boarded or plaster...

blast furnace

(Encyclopedia)CE5 Blast furnace for production of iron blast furnace, structure used chiefly in smelting. The principle involved in this means of extracting metals is that of the reduction of the ores by the ac...

cell, in biology

(Encyclopedia)CE5 Animal cell cell, in biology, the unit of structure and function of which all plants and animals are composed. The cell is the smallest unit in the living organism that is capable of integrati...

nitrocellulose

(Encyclopedia)nitrocellulose, nitric acid ester of cellulose (a glucose polymer). It is usually formed by the action of a mixture of nitric and sulfuric acids on purified cotton or wood pulp. The extent of nitratio...

Liu Shaoqi

(Encyclopedia)Liu Shaoqi or Liu Shao-ch'i both: lyo͞o shou-chē [key], 1898?–1969, Chinese Communist political leader. Liu joined (1920) a Comintern organization in Shanghai, where he studied Russian. While in M...

mesoderm

(Encyclopedia)mesoderm, in biology, middle layer of tissue formed in the gastrula stage of the developing embryo. At the end of the blastula stage, cells of the embryo are arranged in the form of a hollow ball. Con...

molecular orbital theory

(Encyclopedia)molecular orbital theory, detailed explanation of how electrons are distributed in stable molecules. In the simpler valence theory of the chemical bond, each atom in a molecule is assumed to retain it...