General Science Questions (MCQs) for Competitive Examinations

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In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged.

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Multicellular organisms are made up of more than one cell. The development of multicellular organisms is accompanied by cellular specialization and division of labor; cells become efficient in one process and are dependent upon other cells for the necessities of life. Paramecium is single-celled protists naturally found in aquatic habitats. Paramecium is the only genus in the family Parameciidae, which resides within the phylum Ciliophora.

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A virus has a simple structure. It has no internal cellular structure, no cell wall or cell membrane, just the protein coat that holds the string of nucleic acid. It is made only of a nucleic acid + a protein coat. A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria, algae, and archaea.

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The hair follicles have pigment cells that make melanin, a chemical that gives the hair its color. As one ages, these cells start to die. Without pigment, new hair strands grow in lighter and take on various shades of gray, silver, and eventually white.

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Animals, such as mammals and birds, that maintain a constant body temperature regardless of the temperature of the surroundings are called warm blooded. These include birds and mammals. Whales are aquatic mammals hence, being mammal, they are warm blooded. The have a thick layer of fats called blubber underneath their skin to maintain temperature even in cold water of oceans.

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The three organelles that contain DNA are the nucleus, mitochondria and chloroplasts. Mitochondria are unlike most organelles (with an exception of plant chloroplasts) in that they have their own set of DNA and genes that encode proteins. They are specialized structures unique to the cells of animals, plants and fungi.

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The Rock Dove (Columba livia) or Rock Pigeon, is a member of the bird family Columbidae (doves and pigeons). In common usage, this bird is often simply referred to as the “pigeon”. The species includes the domestic pigeon (including the fancy white pigeon).

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Seahorse is the name given to 54 species of small marine fishes in the genus Hippocampus. It comes under Animalia kingdom; Chordata phylum; Actinopterygii class. Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail.

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Cinnamon is a spice obtained from the inner bark of several tree species from the genus Cinnamomum. Cinnamon is used mainly as an aromatic condiment and flavoring additive in a wide variety of cuisines. The aroma and flavor of cinnamon derive from its essential oil and principal component, cinnamaldehyde, as well as numerous other constituents, including eugenol.

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Advancing glaciers distort the shape of the rings of trees because melting ice of glaciers not only increase water level in ocean but also contribute to the weather changes of a place that affect formation of annual rings.