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space medicine

(Encyclopedia)space medicine, study of the medical and biological effects of space travel on living organisms. The principal aim is to discover how well and for how long humans can withstand the extreme conditions ...

Russell, Bertrand Arthur William Russell, 3d Earl

(Encyclopedia)Russell, Bertrand Arthur William Russell, 3d Earl, 1872–1970, British philosopher, mathematician, and social reformer, b. Trelleck, Wales. As with his philosophical stance, Russell's positions on ...

social security

(Encyclopedia)social security, government program designed to provide for the basic economic security and welfare of individuals and their dependents. The programs classified under the term social security differ f...

circulatory system

(Encyclopedia)CE5 Circulatory system circulatory system, group of organs that transport blood and the substances it carries to and from all parts of the body. The circulatory system can be considered as compose...

artificial intelligence

(Encyclopedia)artificial intelligence (AI), the use of computers to model the behavioral aspects of human reasoning and learning. Research in AI is concentrated in some half-dozen areas. In problem solving, one mus...

respiration

(Encyclopedia)CE5 Respiratory system respiration, process by which an organism exchanges gases with its environment. The term now refers to the overall process by which oxygen is abstracted from air and is tran...

Cnidaria

(Encyclopedia)CE5 Internal anatomy of Hydra, representative of the phylum Cnidaria Cnidaria səlĕntəräˈtə [key], phylum of invertebrate animals comprising the sea anemones, corals, jellyfish, and hydroids....

endocrine system

(Encyclopedia)endocrine system ĕnˈdəkrĭn [key], body control system composed of a group of glands that maintain a stable internal environment by producing chemical regulatory substances called hormones. The end...

cancer, in medicine

(Encyclopedia)cancer, in medicine, common term for neoplasms, or tumors, that are malignant. Like benign tumors, malignant tumors do not respond to body mechanisms that limit cell growth. Unlike benign tumors, mali...

fish, in zoology

(Encyclopedia)CE5 Anatomy of a ray-finned fish fish, limbless aquatic vertebrate animal with fins and internal gills. Traditionally the living fish have been divided into three class: the primitive jawless fish...