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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...bacteria
(Encyclopedia)bacteria [pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant king...plant
(Encyclopedia)plant, any organism of the plant kingdom, as opposed to one of the animal kingdom or of the kingdoms Fungi, Protista, or Monera in the five-kingdom system of classification. (A more recent system, sug...space exploration
(Encyclopedia)CE5 Moon mission assembly CE5 Stages in a moon mission shown counterclockwise from launching on the first day to splashdown on the ninth day. space exploration, the investigation of physical co...Browse by Subject
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