General Science Questions (MCQs) for Competitive Examinations

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Magnetite, followed by Hematite – Limonite – Siderite

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Radium is a chemical element with the symbol Ra and atomic number 88. Radium was discovered by Marie Sklodowska Curie, a Polish chemist, and Pierre Curie, a French chemist, in 1898.

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Tungsten has the highest tensile strength of any natural metal, with an ultimate strength of 1510 megapascals. Tungsten has the highest melting point (3422 °C, 6192 °F), lowest vapor pressure (at temperatures above 1650 °C, 3000 °F).

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Alfred Bernhard Nobel was a Swedish chemist, engineer, inventor, businessman, and philanthropist. Atomic number 102 was named after him.

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Holstein Friesian cows are world’s highest-production dairy animals and dominate the global dairy industry. These cows originated in Dutch provinces of North Holland and Friesland, and Schleswig-Holstein in Northern Germany. They are known as Holsteins in North America and Friesians in UK and Ireland.

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Calyptrogen is a layer of rapidly dividing cells at the tip of a plant root, from which the root cap is formed. It occurs in grasses and many other plants. The root cap is formed by several layers of cells that envelop the root tip externally. This covering of cells, of which the outermost ones are dead, envelops and protects the growing tip of root.

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Land snails, insects, birds, and some reptiles excrete uric acid as the major nitrogenous waste. The white, crystalline substance seen in a typical bird or lizard “poop” is actually urine: a little pool of uric acid crystals in a very small amount of water.

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Smallpox was one of the world’s most devastating diseases known to humanity. The last known natural case was in Somalia in 1977. It was declared eradicated in 1980 following a global immunization campaign led by the World Health Organization. Smallpox is caused by infection with the variola virus.

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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 leaves arise in the regions of the plant known as the plant nodes and are therefore the point of attachment of the leaves. The region of the plant between two nodes is known as the internode. The angle between the upper surface of the leaf and the stem from which it arises is known as the axil.