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Fraternal Twins
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or ''dizygotic'' ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In rare cases twins can have the same mother and different fathers ( heteropaternal superfecundation). In contrast, a fetus that develops alone in the womb (the much more common case, in humans) is called a ''singleton'', and the general term for one offspring of a multiple birth is a ''multiple''. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgängers. Statistics The human twin birth rate in the United States rose 76% fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mark And Scott Kelly At The Johnson Space Center, Houston Texas
Mark may refer to: Currency * Bosnia and Herzegovina convertible mark, the currency of Bosnia and Herzegovina * East German mark, the currency of the German Democratic Republic * Estonian mark, the currency of Estonia between 1918 and 1927 * Finnish markka ( sv, finsk mark, links=no), the currency of Finland from 1860 until 28 February 2002 * Mark (currency), a currency or unit of account in many nations * Polish mark ( pl, marka polska, links=no), the currency of the Kingdom of Poland and of the Republic of Poland between 1917 and 1924 German * Deutsche Mark, the official currency of West Germany from 1948 until 1990 and later the unified Germany from 1990 until 2002 * German gold mark, the currency used in the German Empire from 1873 to 1914 * German Papiermark, the German currency from 4 August 1914 * German rentenmark, a currency issued on 15 November 1923 to stop the hyperinflation of 1922 and 1923 in Weimar Germany * Lodz Ghetto mark, a special currency for Lodz Ghetto. * Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
