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nitrate

(Encyclopedia)nitrate, chemical compound containing the nitrate (NO3) radical. Nitrates are salts or esters of nitric acid, HNO3, formed by replacing the hydrogen with a metal (e.g., sodium or potassium) or a radic...

cave

(Encyclopedia)cave, a cavity in the earth's surface usually large enough for a person to enter. Caves may be formed by the chemical and mechanical action of a stream upon soluble or soft rock, of rainwater seeping ...

dust, atmospheric

(Encyclopedia)dust, atmospheric, minute particles slowly settling or suspended by slight currents and existing in varying amounts in all air. There is least dust at high levels over the ocean and most at low levels...

ulcer

(Encyclopedia)ulcer, open sore or circumscribed erosion, usually slow to heal, on the skin or mucous membranes. It may develop as a result of injury; because of a circulatory disturbance, e.g., in varicose veins or...

Escherichia coli

(Encyclopedia)Escherichia coli ĕshˌərĭkˈēə kōˈlī [key], common bacterium that normally inhabits the intestinal tracts of humans and animals, but can cause infection in other parts of the body, especially ...

flax

(Encyclopedia)flax, common name for members of the Linaceae, a family of annual herbs, especially members of the genus Linum, and for the fiber obtained from such plants. The flax of commerce (several varieties of ...

biological warfare

(Encyclopedia)biological warfare, employment in war of microorganisms to injure or destroy people, animals, or crops; also called germ or bacteriological warfare. Limited attempts have been made in the past to spre...

growth hormone

(Encyclopedia)growth hormone or somatotropin sōmătˌətrōˈpən [key], glycoprotein hormone released by the anterior pituitary gland that is necessary for normal skeletal growth in humans (see protein). Evidence...

clone

(Encyclopedia)clone, group of organisms, all of which are descended from a single individual through asexual reproduction, as in a pure cell culture of bacteria. Except for changes in the hereditary material that c...

liver

(Encyclopedia)liver, largest glandular organ of the body, weighing about 3 lb (1.36 kg). It is reddish brown in color and is divided into four lobes of unequal size and shape. The liver lies on the right side of th...