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nuclear reactor
(Encyclopedia)CE5 Power reactor system nuclear reactor, device for producing controlled release of nuclear energy. Reactors can be used for research or for power production. A research reactor is designed to pr...rodent
(Encyclopedia)rodent, member of the mammalian order Rodentia, characterized by front teeth adapted for gnawing and cheek teeth adapted for chewing. The Rodentia is by far the largest mammalian order; nearly half of...Mollusca
(Encyclopedia)Mollusca məlŭsˈkə [key], taxonomic name for the one of the largest phyla of invertebrate animals (Arthropoda is the largest) comprising more than 50,000 living mollusk species and about 35,000 fos...Chordata
(Encyclopedia)CE5 Common features in representative groups of the phylum Chordata Chordata kôrdāˈtə, –däˈ– [key], phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal ...dolphin, aquatic mammal
(Encyclopedia)dolphin, aquatic mammal, any of the small toothed whales of the family Delphinidae, numbering more than 50 species. These include the true, or beaked, dolphins, the killer whale, the pilot whale, and ...whaling
(Encyclopedia)whaling, the hunting of whales for the oil that can be rendered from their flesh, for meat, and for baleen (whalebone). Historically, whale oil was economically the most important. In 1932–33, par...water pollution
(Encyclopedia)water pollution, contamination of water resources by harmful wastes; see also sewerage, water supply, pollution, and environmentalism. The United States has enacted extensive federal legislation to ...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...Nevada
(Encyclopedia)CE5 Nevada nəvădˈə, –vä– [key], far western state of the United States. It is bordered by Utah (E), Arizona (SE), California (SW, W), and Oregon and Idaho (N). In the 20th cent. the ...insect
(Encyclopedia)CE5 External anatomy of a female grasshopper, representative of the class Insecta insect, invertebrate animal of the class Insecta of the phylum Arthropoda. Like other arthropods, an insect has a ...Browse by Subject
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