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Twin Towers
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of Twin Last 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 very rare cases, fraternal or (semi-) identical 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 doppelgänger. Statistics The human twin birth rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauch Twins
William John Mauch (July 6, 1921 – September 29, 2006) and his identical twin brother, Robert Joseph Mauch (July 6, 1921 – October 15, 2007), were child actors in the 1930s. They had starring roles in the 1937 film ''The Prince and the Pauper (1937 film), The Prince and the Pauper'', based on the The Prince and the Pauper, 1881 novel of the same name by Mark Twain. Early life Billy and Bobby were born in Peoria, Illinois, Peoria, Illinois, to Felix, an employee of the Toledo, Peoria & Western Railroad and Marguerite Mauch, née Burley. Billy was older than Bobby by ten minutes. They began singing and acting in radio at the age of seven and later appeared in print advertisements before signing a contract with Warner Bros. Career After moving with their mother to Hollywood in 1935, Billy was cast as the young title character in the film ''Anthony Adverse'' because he resembled Fredric March, who was to play Adverse as an adult. His brother Bobby was his stand-in for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Africa
Central Africa (French language, French: ''Afrique centrale''; Spanish language, Spanish: ''África central''; Portuguese language, Portuguese: ''África Central'') is a subregion of the African continent comprising various countries according to different definitions. Middle Africa is an analogous term used by the United Nations in its United Nations geoscheme for Africa, geoscheme for Africa and consists of the following countries: Angola, Cameroon, Central African Republic, Chad, Democratic Republic of the Congo, Republic of the Congo, Equatorial Guinea, Gabon, and São Tomé and Príncipe. The United Nations Office for Central Africa also includes Burundi and Rwanda in the region, which are considered part of East Africa in the geoscheme. These eleven countries are members of the Economic Community of Central African States (ECCAS). Six of those countries (Cameroon, Central African Republic, Chad, Equatorial Guinea, Gabon, and Republic of the Congo) are also members of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatozoon
A spermatozoon (; also spelled spermatozoön; : spermatozoa; ) is a motile sperm cell (biology), cell produced by male animals relying on internal fertilization. A spermatozoon is a moving form of the ploidy, haploid cell (biology), cell that is the male gamete that Fertilization, joins with an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear gene, genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing an X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed in Antonie van Leeuwenhoek's laboratory in 1677. Mammalian spermatozoa Humans The sperm cell of ''Homo sapiens'' is the small Gamete, reproductive cell produced by m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilisation
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. While processes such as insemination or pollination, which happen before the fusion of gametes, are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms, the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
