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bone

(Encyclopedia)CE5 Bone bone, hard tissue that forms the skeleton of the body in vertebrate animals. In the very young, the skeleton is composed largely of cartilage and is therefore pliable, reducing the incide...

hydra, in zoology

(Encyclopedia)hydra hīˈdrə [key], common name for freshwater organisms in the phylum Cnidaria, which includes jellyfish, sea anemones, and corals. Hydras are widely distributed in lakes, ponds, and sluggish stre...

cambium

(Encyclopedia)cambium kămˈbēəm [key], thin layer of generative tissue lying between the bark and the wood of a stem, most active in woody plants. The cambium produces new layers of phloem on the outside and of ...

ectoderm

(Encyclopedia)ectoderm, layer of cells that covers the surface of an animal embryo after the process of gastrulation has occurred. This outer layer, together with the endoderm, or inner layer, is present in all ear...

spinal cord

(Encyclopedia)spinal cord, the part of the nervous system occupying the hollow interior (vertebral canal) of the series of vertebrae that form the spinal column, technically known as the vertebral column. Extending...

Patagonia

(Encyclopedia)Patagonia pätägōˈnyä [key], region, c.300,000 sq mi (777,000 sq km), primarily in S Argentina, S of the Río Colorado and E of the Andes, but including extreme SE Chile and N Tierra del Fuego. Pa...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

Leyden jar

(Encyclopedia)Leyden jar līˈdən [key], form of capacitor invented at the Univ. of Leiden in the 18th cent. It consists of a narrow-necked glass jar coated over part of its inner and outer surfaces with conductiv...

corns and calluses

(Encyclopedia)corns and calluses, thickenings of the outer layer of skin where there is irritation or constant pressure. Corns are cone-shaped with their points protruding into the dermis, or inner layer of skin. T...

fascia

(Encyclopedia)fascia făshˈēə [key], fibrous tissue network located between the skin and the underlying structure of muscle and bone. Fascia is composed of two layers, a superficial layer and a deep layer. Super...