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space science

(Encyclopedia)space science, body of scientific knowledge as it relates to space exploration; it is sometimes also called astronautics. Space science draws on the conventional sciences of physics, chemistry, biolog...

microscope

(Encyclopedia)CE5 Compound microscope microscope, optical instrument used to increase the apparent size of an object. The electron microscope, which is not limited by the powers of optical lenses and light,...

plant

(Encyclopedia)plant, any organism of the plant kingdom, as opposed to one of the animal kingdom or of the kingdoms Fungi, Protista, or Monera in the five-kingdom system of classification. (A more recent system, sug...

mutation

(Encyclopedia)mutation, in biology, a sudden, random change in a gene, or unit of hereditary material, that can alter an inheritable characteristic. Most mutations are not beneficial, since any change in the delica...

race

(Encyclopedia)race, one of the group of populations regarded as constituting humanity. The differences that have historically determined the classification into races are predominantly physical aspects of appearanc...

transplantation, medical

(Encyclopedia)transplantation, medical, surgical procedure by which a tissue or organ is removed and replaced by a corresponding part, usually from another part of the body or from another individual. A life-saving...

sex

(Encyclopedia)sex, term used to refer both to the two groups distinguished as males and females, and to the anatomical and physiological characteristics associated with maleness and femaleness. Sex relates to the t...

chemical bond

(Encyclopedia)chemical bond, mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the for...

ecology

(Encyclopedia)ecology, study of the relationships of organisms to their physical environment and to one another. The study of an individual organism or a single species is termed autecology; the study of groups of ...

Kant, Immanuel

(Encyclopedia)Kant, Immanuel ĭmänˈo͞oĕl känt [key], 1724–1804, German metaphysician, one of the greatest figures in philosophy, b. Königsberg (now Kaliningrad, Russia). The impact of Kant's work has be...