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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...

tuberculosis

(Encyclopedia)tuberculosis (TB), contagious, wasting disease caused by any of several mycobacteria. The most common form of the disease is tuberculosis of the lungs (pulmonary consumption, or phthisis), but the int...

molecule

(Encyclopedia)molecule mŏlˈəkyo͞ol [key] [New Lat.,=little mass], smallest particle of a compound that has all the chemical properties of that compound. A single atom is usually not referred to as a molecule, a...

wolf

(Encyclopedia)wolf, carnivorous mammal of the genus Canis in the dog family. Once distributed over most of the Northern Hemisphere, wild wolves are now confined to the wilder parts of a reduced range. Three wolf sp...

fish, in zoology

(Encyclopedia)CE5 Anatomy of a ray-finned fish fish, limbless aquatic vertebrate animal with fins and internal gills. Traditionally the living fish have been divided into three class: the primitive jawless fish...

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...

medicine

(Encyclopedia)medicine, the science and art of treating and preventing disease. Modern medicine, characterized by growing specialization and a complex diagnostic and therapeutic technology, faces problems in the...

Jefferson, Thomas

(Encyclopedia)Jefferson, Thomas, 1743–1826, 3d President of the United States (1801–9), author of the Declaration of Independence, and apostle of agrarian democracy. After 1809, Jefferson lived in retirem...

cancer, in medicine

(Encyclopedia)cancer, in medicine, common term for neoplasms, or tumors, that are malignant. Like benign tumors, malignant tumors do not respond to body mechanisms that limit cell growth. Unlike benign tumors, mali...

science

(Encyclopedia)science [Lat. scientia=knowledge]. For many the term science refers to the organized body of knowledge concerning the physical world, both animate and inanimate, but a proper definition would also hav...