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insulin

(Encyclopedia)insulin, hormone secreted by the β cells of the islets of Langerhans, specific groups of cells in the pancreas. Insufficiency of insulin in the body results in diabetes. Insulin was one of the first ...

pesticide

(Encyclopedia)pesticide, biological, physical, or chemical agent used to kill plants or animals that are harmful to people; in practice, the term pesticide is often applied only to chemical agents. Various pesticid...

Cretaceous period

(Encyclopedia)Cretaceous period krĭtāˈshəs [key], third and last period of the Mesozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), lasting from approximately 144 to 65 millio...

Northern Mariana Islands

(Encyclopedia)Northern Mariana Islands märēäˈnä [key], officially Commonwealth of the Northern Mariana Islands, a self-governing entity in association with the United States (2015 est. pop. 55,000), c.185 sq m...

lubrication

(Encyclopedia)lubrication, introduction of a substance between the contact surfaces of moving parts to reduce friction and to dissipate heat. A lubricant may be oil, grease, graphite, or any substance—gas, liquid...

Natives, Middle American

(Encyclopedia)Natives, Middle American or Mesoamerican, aboriginal peoples living in the area between present-day United States and South America. Although most of Mexico is geographically considered part of North ...

tapeworm

(Encyclopedia)tapeworm, name for the parasitic flatworms forming the class Cestoda. All tapeworms spend the adult phase of their lives as parasites in the gut of a vertebrate animal (called the primary host). Most ...

Punic Wars

(Encyclopedia)Punic Wars, three distinct conflicts between Carthage and Rome. When they began, Rome had nearly completed the conquest of Italy, while Carthage controlled NW Africa and the islands and the commerce o...

jewelry

(Encyclopedia)jewelry, personal adornments worn for ornament or utility, to show rank or wealth, or to follow superstitious custom or fashion. The most universal forms of jewelry are the necklace, bracelet, ring, p...

Romanov

(Encyclopedia)Romanov rōˈmənŏf, Rus. rəmäˈnəf [key], ruling dynasty of Russia from 1613 to 1917. The name Romanov was adopted in the 16th cent. by a family of boyars (great nobles) that traced its beginning...