sudden variation of level
71Rules of chess — The rules of chess (also known as the laws of chess) are rules governing the play of the game of chess. While the exact origins of chess are unclear, modern rules first took form during the Middle Ages. The rules c …
72Solar cycle — The solar cycle, or the solar magnetic activity cycle, is the main source of periodic variation of all solar phenomena driving variations in space weather. [ [http://www7.nationalacademies.org/ssb/SSB Space weather97.pdf Space Weather: A Research …
73wood — wood1 woodless, adj. /wood/, n. 1. the hard, fibrous substance composing most of the stem and branches of a tree or shrub, and lying beneath the bark; the xylem. 2. the trunks or main stems of trees as suitable for architectural and other… …
74Wood — /wood/, n. 1. Grant, 1892 1942, U.S. painter. 2. Leonard, 1860 1927, U.S. military doctor and political administrator. * * * I Hard, fibrous material formed by the accumulation of secondary xylem produced by the vascular cambium. It is the… …
75Cambrian Period — Oldest time division of the Paleozoic Era. During the Cambrian, 543–490 million years ago, there were widespread seas and several scattered landmasses. The largest continent was Gondwana. The average climate was probably warmer than today, with… …
77Audio system measurements — are made for several purposes. Designers take measurements so that they can specify the performance of a piece of equipment. Maintenance engineers make them to ensure equipment is still working to specification, or to ensure that the cumulative… …
78Binge drinking — New Year s Eve is traditionally a time when many drink excessive amounts of alcohol. This picture is from a 1912 postcard mailed in the United States …
79Poland — /poh leuhnd/, n. a republic in E central Europe, on the Baltic Sea. 38,700,291; ab. 121,000 sq. mi. (313,400 sq. km). Cap.: Warsaw. Polish, Polska. * * * Poland Introduction Poland Background: Poland is an ancient nation that was conceived around …
80Microevolution — Part of a series on Evolutionary Biology …
