Browse "Nature & Geography"

Displaying 721-740 of 895 results
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Seaweeds

Seaweeds are multicellular marine algae, visible to the naked eye. They extend from the uppermost reaches of sea spray on the shore to the lower limits of light beneath the surface of the water.

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Sedge

Sedge is a grasslike plant common throughout temperate and cold regions. The genus name, Carex (family Cyperaceae), is probably derived from keiro, referring to the sharp leaf margins.

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Sedimentary Rock

 Only about 5% of the Earth's crust is composed of sedimentary rocks, but they cover 70-75% of the exposed surface and contain many economically important minerals, as well as coal and petroleum.

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Seed Plants

The common feature uniting seed plants is the "seed habit," a unique method of sexual reproduction. In all vascular plants, the conspicuous plant is a spore producer (sporophyte) that alternates, in the life cycle, with a sexual phase (gametophyte).

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Shark

A shark is a marine fish with cartilaginous skeleton belonging to subclass Elasmobranchii, class Chondrichthyes, order Pleurotremata.

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Shearwater

The shearwater (order Procellariiformes, family Procellariidae) is a medium-sized seabird.

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Shrew

Shrew (Soricidae), family of small insectivores represented today by approximately 250 species worldwide, 16 in Canada.

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Shrike

Shrike is the common name for the family Laniidae of singing birds.

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Shrimp

Shrimp are decapods ("10-footed") crustacean, differing from other decapods in being adapted for swimming, a fact reflected in the large, laterally compressed abdomen and well-developed pairs of swimming legs.

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Silica

Silica, or silicon dioxide (SiO2), occurs as the MINERAL quartz and is the most abundant mineral of the Earth's crust. It also occurs in the skeletal parts of some animals (eg, certain protozoa) and various plants.

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Silver

Important producing countries now are Mexico, Peru, the Commonwealth of Independent States, the US, Canada, Australia, Chile, Poland and China. Photographic films and papers account for about 25% of the demand for silver.

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Silviculture

Silviculture is the branch of FORESTRY that deals with establishing, caring for and reproducing stands of trees for a variety of forest uses including wildlife habitat, timber production and outdoor recreation.

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Skunk

 The skunk is a carnivorous, cat-sized mammal. Skunks were previously considered as part of the weasel family (Mustelidae) but DNA research has placed them in their own family, Mephitidae.

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Sky

The sky appears its deepest blue when the air is dry and clean. Water vapour and dust scatter all colours of light, causing the blue to appear washed-out and pale.

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Slug

Slug is a common name for several terrestrial pulmonate and numerous marine gilled species of gastropod molluscs conspicuous by the lack of an exposed shell.

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Smelt

Smelt (Osmeridae), family of small, iridescent fishes of class Osteichthyes, found in coastal seas, streams and lakes of the northern hemisphere.

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Snail

Snail, common name for members of several groups of gastropod molluscs. Snails inhabit all moist habitats, but most forms are marine.

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Snake

A snake is a long, slender reptile of the suborder Serpentes, order Squamata (which also includes lizards). In Canada, 26 species and one hybrid are native, with most species occurring in the southern part of the country.

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Snipe

Snipe is the name given to 19 species of small to medium-sized shorebirds (254-406 mm) of the sandpiper family.