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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...

Platyhelminthes

(Encyclopedia)CE5 A. Planaria, representative of the phylum Platyhelminthes B. Internal anatomy of Planaria Platyhelminthes plătˌēhĕlmĭnˈthēz [key], phylum containing about 20,000 species of soft-bodied,...

horse

(Encyclopedia)CE5 General anatomy of a horse horse, hoofed, herbivorous mammal now represented by a single extant genus, Equus. The term horse commonly refers only to the domestic Equus caballus and to the wild...

cat

(Encyclopedia)cat, name applied broadly to the carnivorous mammals constituting the family Felidae, and specifically to the domestic cat, Felis catus. The great roaring cats, the lion, tiger, and leopard are anatom...

evolution

(Encyclopedia)CE5 Plant and animal evolution [Modified from Alfred Gunderson in Brooklyn Botanic Garden Leaflets, Ser. 18, No. 4 (1930); used by permission.] evolution, concept that embodies the belief that ex...

air pollution

(Encyclopedia)air pollution, contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are t...

Arctic, the

(Encyclopedia)CE5 Arctic, the northernmost area of the earth, centered on the North Pole. The arctic regions are not coextensive with the area enclosed by the Arctic Circle (lat. 66°30′N) but are usually defi...

National Parks and Monuments (table)

(Encyclopedia)National Parks and Monuments 1 National Parks and Monuments National Monuments National and International Historic Sites and Historical Parks National Memorials National Battlef...

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