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ozone layer

(Encyclopedia)ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. Ozone in the ozone...

water, desalination of

(Encyclopedia)water, desalination of, process of removing soluble salts from water to render it suitable for drinking, irrigation, or industrial uses. The principal methods used for desalination include distillatio...

slime mold

(Encyclopedia)slime mold or slime fungus, a heterotrophic organism once regarded as a fungus but later classified with the Protista. In a recent system of classification based on analysis of nucleic acid (genetic m...

teeth

(Encyclopedia)CE5 A. Upper and lower teeth of an adult B. Cross section of a molar teeth, hard, calcified structures embedded in the bone of the jaws of vertebrates that perform the primary function of masticat...

antibiotic

(Encyclopedia)antibiotic, any of a variety of substances, usually obtained from microorganisms, that inhibit the growth of or destroy certain other microorganisms. Although for centuries preparations derived from ...

interstellar matter

(Encyclopedia)interstellar matter, matter in a galaxy between the stars, known also as the interstellar medium. The interstellar gas, which constitutes about 99% of the interstellar matter, consists mostly of hyd...

concrete

(Encyclopedia)concrete, structural masonry material made by mixing broken stone or gravel with sand, cement, and water and allowing the mixture to harden into a solid mass. The cement is the chemically active eleme...

crystal

(Encyclopedia)CE5 Types of crystal crystal, a solid body bounded by natural plane faces that are the external expression of a regular internal arrangement of constituent atoms, molecules, or ions. The formation...

prion

(Encyclopedia)prion prēˈŏn [key], abnormal form of a protein found in mammals, now generally believed to cause a group of diseases known as prion diseases or transmissible spongiform encephalopathies, which are ...

protozoan

(Encyclopedia)protozoan prōˌtəzōˈən [key], informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms ...