1. The correct answer is: (c) CFCs; Ozone. In 1987, the Montreal Protocol was signed under the United Nations Environment Programme (UNEP). It aimed to freeze the production of CFCs (chlorofluorocarbons) because they were damaging the ozone layer in the atmosphere, which protects the Earth from harmfulRead more

    The correct answer is: (c) CFCs; Ozone. In 1987, the Montreal Protocol was signed under the United Nations Environment Programme (UNEP). It aimed to freeze the production of CFCs (chlorofluorocarbons) because they were damaging the ozone layer in the atmosphere, which protects the Earth from harmful ultraviolet (UV) rays. This helped prevent further ozone depletion.

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  2. The correct answer is: (c) scattering of light. When sunlight enters the atmosphere, it meets tiny particles like dust and gas molecules. These particles scatter the light in all directions, rather than just letting it pass straight. This phenomenon is called scattering of light, which is also why tRead more

    The correct answer is: (c) scattering of light. When sunlight enters the atmosphere, it meets tiny particles like dust and gas molecules. These particles scatter the light in all directions, rather than just letting it pass straight. This phenomenon is called scattering of light, which is also why the sky looks blue during the day.

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  3. The correct answer is: (d) behind the mirror and its position varies according to the object distance. A convex mirror always forms a virtual, upright, and smaller image of an object. This image appears behind the mirror, not on the same side as the object. Its position changes slightly if the objecRead more

    The correct answer is: (d) behind the mirror and its position varies according to the object distance. A convex mirror always forms a virtual, upright, and smaller image of an object. This image appears behind the mirror, not on the same side as the object. Its position changes slightly if the object moves, but it always remains virtual and smaller, making it useful for vehicle mirrors.

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  4. The correct answer is (c) Growth hormones under the influence of the enzymes coded by a gene. The height of a plant is controlled by growth hormones like auxins and gibberellins. These hormones function under the regulation of enzymes coded by genes. Genes produce proteins and enzymes that influenceRead more

    The correct answer is (c) Growth hormones under the influence of the enzymes coded by a gene. The height of a plant is controlled by growth hormones like auxins and gibberellins. These hormones function under the regulation of enzymes coded by genes. Genes produce proteins and enzymes that influence hormone activity, thereby controlling growth patterns, elongation, and ultimately determining the height of the plant.

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  5. The correct answer is: (c) lack of oxygen and formation of lactic acid. When a sportsman resumes heavy exercise after a long break, his muscles may not get enough oxygen. This oxygen deficit causes anaerobic respiration in muscles, converting glucose into lactic acid instead of carbon dioxide and waRead more

    The correct answer is: (c) lack of oxygen and formation of lactic acid. When a sportsman resumes heavy exercise after a long break, his muscles may not get enough oxygen. This oxygen deficit causes anaerobic respiration in muscles, converting glucose into lactic acid instead of carbon dioxide and water. Accumulation of lactic acid leads to muscular cramps and fatigue.

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