natural periods
121Mexico — /mek si koh /, n. 1. a republic in S North America. 97,563,374; 761,530 sq. mi. (1,972,363 sq. km). Cap.: Mexico City. 2. a state in central Mexico. 6,245,000; 8268 sq. mi. (21,415 sq. km). Cap.: Toluca. 3. Gulf of, Mexican, Golfo de México /gawl …
122History of the Earth — For the history of modern humans, see History of the world. Geological time put in a diagram called a geological clock, showing the relative lengths of the eons of the Earth s history The history of the Earth describes the most important events… …
123GEOGRAPHICAL SURVEY — Names The name Ereẓ Israel (the Land of Israel) designates the land which, according to the Bible was promised as an inheritance to the Israelite tribes. In the course of time it came to be regarded first by the Jews and then also by the… …
124Chemical element — The periodic table of the chemical elements A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus.[1] Familiar examples of …
125Evolution — This article is about evolution in biology. For other uses, see Evolution (disambiguation). For a generally accessible and less technical introduction to the topic, see Introduction to evolution. Part of a series on …
126Greenhouse gas — Simple diagram of greenhouse effect. A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.[1] …
127Classical Latin — Latinitas Latin inscription in the Colosseum …
128Shifting cultivation — For methods, see slash and burn Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. This system often involves clearing of a piece of land followed by several years of wood harvesting… …
