The document discusses the phases of the moon. It explains that the moon gets its light from the sun and revolves around the earth every 28-31 days. As it revolves, the shape of the moon changes through phases such as new moon, crescent moon, quarter moon, gibbous moon, and full moon depending on how much of the illuminated side is visible to observers on earth.
Rivers of south americaa & north americaArijit Sarkar
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The document summarizes key rivers of South America, providing their lengths, sources, mouths, and countries they flow through. The longest is the Amazon at 6,800 km, sourcing in Peru and flowing through Brazil before reaching the Atlantic. The second longest is the Orinoco at 2,140 km, sourcing in Venezuela and Colombia and also emptying into the Atlantic. The Parana is 1,090 km long, forming at the union of two Brazilian rivers and flowing through Brazil, Paraguay and Argentina before joining the Paraguay River to empty into the Atlantic via the Rio de la Plata.