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Swammerdam, Jan

(Encyclopedia)Swammerdam, Jan yän väˈmərdäm [key], 1637–80, Dutch naturalist. He was a pioneer in the use of the microscope. Before he turned to religious contemplation his chief interest was the study of in...

biopsy

(Encyclopedia)biopsy bīäpˈsē [key], examination of cells or tissues removed from a living organism. Excised material may be studied in order to diagnose disease or to confirm findings of normality. Preparatory ...

Missouri River basin project

(Encyclopedia)Missouri River basin project, comprehensive plan authorized in 1944 for the coordinated development of water resources of the Missouri River and its tributaries, draining an area of c.513,300 sq mi (1...

gnat

(Encyclopedia)gnat, common name for any one of a number of small, fragile-looking two-winged flies of the suborder Nematocera, order Diptera, which includes the families Tipulidae (crane flies), Bibionidae (hairfli...

Almoravids

(Encyclopedia)Almoravids ălmôrˈəvĭdz [key], Berber Muslim dynasty that ruled Morocco and Muslim Spain in the 11th and 12th cent. The Almoravids may have originated in what is now Mauritania. The real founder w...

Tula , ancient city, Mexico

(Encyclopedia)Tula to͞oˈlä [key], ancient city in the present state of Hidalgo, central Mexico. It was one of the chief urban centers of the Toltec. The city is believed to be Tollán, the legendary Toltec capit...

White Nile

(Encyclopedia)White Nile, river, one of the chief tributaries of the Nile, E Africa. The name is sometimes used for the 600 mi (970 km) long section of the river known as the Bahr el Abiad that extends upstream fro...

multiple birth

(Encyclopedia)multiple birth, bringing forth of more than one offspring at birth. Although many smaller mammals bear several young at a time, multiple births are relatively uncommon in humans and other primates. Tw...

reproductive system

(Encyclopedia)CE5 Reproductive system reproductive system, in animals, the anatomical organs concerned with production of offspring. In humans and other mammals the female reproductive system produces the femal...

Leeuwenhoek, Antony van

(Encyclopedia)Leeuwenhoek, Antony van änˈtōnē vän lāˈvənho͞okˌ [key], 1632–1723, Dutch student of natural history and maker of microscopes, b. Delft. His use of lenses in examining cloth as a draper's a...