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Chomsky, Noam

(Encyclopedia)Chomsky, Noam nōm chŏmˈskē [key], 1928–, educator and linguist, b. Philadelphia. Chomsky, who has taught at the Massachusetts Institute of Technology since 1955, developed a theory of transforma...

free will

(Encyclopedia)free will, in philosophy, the doctrine that an individual, regardless of forces external to him, can and does choose at least some of his actions. The existence of free will is challenged by determini...

anesthesia

(Encyclopedia)anesthesia ănĭsthēˈzhə [key] [Gr.,=insensibility], loss of sensation, especially that of pain, induced by drugs, especially as a means of facilitating safe surgical procedures. Early modern medic...

skeleton, in anatomy

(Encyclopedia)CE5 Human skeleton skeleton, in anatomy, the stiff supportive framework of the body. The two basic types of skeleton found among animals are the exoskeleton and the endoskeleton. The shell of the ...

sickle cell disease

(Encyclopedia)sickle cell disease or sickle cell anemia, inherited disorder of the blood in which the oxygen-carrying hemoglobin pigment in erythrocytes (red blood cells) is abnormal. This “hemoglobin-S” crysta...

cocaine

(Encyclopedia)cocaine kōkānˈ, kōˈkān [key], alkaloid drug derived from the leaves of the coca shrub. A commonly abused illegal drug, cocaine has limited medical uses, most often in surgical applications that ...

Platyhelminthes

(Encyclopedia)CE5 A. Planaria, representative of the phylum Platyhelminthes B. Internal anatomy of Planaria Platyhelminthes plătˌēhĕlmĭnˈthēz [key], phylum containing about 20,000 species of soft-bodied,...

psychology

(Encyclopedia)psychology, science or study of the thought processes and behavior of humans and other animals in their interaction with the environment. Psychologists study processes of sense perception, thinking, l...

cholesterol

(Encyclopedia)CE5 cholesterol kəlĕsˈtərōlˌ [key], fatty lipid found in the body tissues and blood plasma of vertebrates; it is only sparingly soluble in water, but much more soluble in some organic solvent...

Tay-Sachs disease

(Encyclopedia)Tay-Sachs disease tāˈ-săksˈ [key], rare hereditary disease caused by a genetic mutation that leaves the body unable to produce an enzyme necessary for fat metabolism in nerve cells, producing cent...