Green wiki:
>For other uses, see Green (disambiguation). Green is a color seen commonly in nature. Many plants are green mainly because of a complex chemical known as chlorophyll which is involved in photosynthesis.Green light has a wavelength of roughly 520â570 nm and is one of the additive primary colors. It is the complement of magenta. Many artists, however, continue to use a traditional color theory in which the complement of green is considered to be red.People who are red-green color blind can often distinguish between the two colors but confuse them with other colors, for example, bright green with yellow; dark green with brown.
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Sky wiki:
>For other uses, see Sky (disambiguation). The sky is (roughly) that part of the atmosphere or of outer space visible from the surface of the earth (or any other planet; see Skies of other planets).). Birds, airplanes, and kites are often considered to fly in the sky. It is difficult to define precisely for several reasons. During daylight the sky has the appearance of an opaque blue surface, but this is the result of the air refracting sunlight. There is no "blue object" above the earth in any normal sense, so it is hard to say what object the sky is. The sky is thus sometimes defined as the denser gaseous zone of a planet's atmosphere. At night the sky has the appearance of a black surface or region scattered with stars. But if we then say that the sky is the entire visible universe, it would not be the same thing we see during the day.
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Metal wiki:
>For alternative meanings see metal (disambiguation). In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionisation and bonding properties, along with the metalloids and nonmetals. On the periodic table, a diagonal line drawn from boron (B) to polonium (Po) separates the metals from the nonmetals. Elements on this line are metalloids, sometimes called semi-metals; elements to the lower left are metals; elements to the upper right are nonmetals.
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