many of these compounds are not formed in any
41spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
42chemical industry — Introduction complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives. Although the chemical industry may be described simply as the industry that uses chemistry and… …
43community ecology — Introduction study of the organization and functioning of communities (community), which are assemblages of interacting populations of the species living within a particular area or habitat. As populations of species interact with one …
44endocrine system, human — ▪ anatomy Introduction group of ductless glands (gland) that regulate body processes by secreting chemical substances called hormones (hormone). Hormones act on nearby tissues or are carried in the bloodstream to act on specific target organs… …
45chemoreception — chemoreceptive /kee moh ri sep tiv, kem oh /, adj. /kee moh ri sep sheuhn, kem oh /, n. the physiological response to chemical stimuli. [1915 20; CHEMO + RECEPTION] * * * Sensory process by which organisms respond to external chemical stimuli, by …
46India — /in dee euh/, n. 1. Hindi, Bharat. a republic in S Asia: a union comprising 25 states and 7 union territories; formerly a British colony; gained independence Aug. 15, 1947; became a republic within the Commonwealth of Nations Jan. 26, 1950.… …
47soil — soil1 soilless, adj. /soyl/, n. 1. the portion of the earth s surface consisting of disintegrated rock and humus. 2. a particular kind of earth: sandy soil. 3. the ground as producing vegetation or as cultivated for its crops: fertile soil. 4. a… …
48Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
49human disease — Introduction an impairment of the normal state of a human being that interrupts or modifies its vital functions. health versus disease Before human disease can be discussed, the meanings of the terms health, physical fitness, illness …
50mineral deposit — Introduction aggregate of a mineral in an unusually high concentration. About half of the known chemical elements (chemical element) possess some metallic (metal) properties. The term metal, however, is reserved for those chemical… …
