1. The statement that vultures have the least amount of pesticides is false. In fact, they have the highest concentration due to biological magnification, where toxic substances like pesticides increase as we move up the food chain. The reason, however, is true, as vultures occupy the last trophic leveRead more

    The statement that vultures have the least amount of pesticides is false. In fact, they have the highest concentration due to biological magnification, where toxic substances like pesticides increase as we move up the food chain. The reason, however, is true, as vultures occupy the last trophic level and receive only 10% of energy from the previous level. But this reason doesn’t explain the assertion. Therefore, the correct relationship between the two statements is false assertion and true reason. The correct option is (D).

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  2. The tallness of pea plants is controlled by a gene that produces a specific enzyme responsible for synthesising growth-promoting hormones. The presence of this enzyme results in tall plants, while its absence causes dwarfness. Hence, both the assertion and the reason are true, and the reason correctRead more

    The tallness of pea plants is controlled by a gene that produces a specific enzyme responsible for synthesising growth-promoting hormones. The presence of this enzyme results in tall plants, while its absence causes dwarfness. Hence, both the assertion and the reason are true, and the reason correctly explains the assertion. This experiment demonstrates how genes control traits by producing proteins or enzymes that influence the physical characteristics of an organism. The correct option is (A).

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  3. Among the given options, using plastic as packaging material leads to the accumulation of non-biodegradable waste. Plastics take hundreds of years to decompose, polluting land and water bodies and harming animals who ingest them. In contrast, practices like organic farming, tree plantation, and compRead more

    Among the given options, using plastic as packaging material leads to the accumulation of non-biodegradable waste. Plastics take hundreds of years to decompose, polluting land and water bodies and harming animals who ingest them. In contrast, practices like organic farming, tree plantation, and composting promote biodegradability and environmental balance. Hence, the increase in plastic usage by humans is the primary reason for the rise in non-biodegradable substances in the environment. The correct option is (C).

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  4. Ozone near the Earth’s surface is poisonous, but in the stratosphere, it forms a protective ozone layer. This layer absorbs harmful ultraviolet (UV) radiation from the Sun, preventing skin cancer, cataracts, and damage to living organisms. The correct statements are (ii), (iii), and (iv) — ozone isRead more

    Ozone near the Earth’s surface is poisonous, but in the stratosphere, it forms a protective ozone layer. This layer absorbs harmful ultraviolet (UV) radiation from the Sun, preventing skin cancer, cataracts, and damage to living organisms. The correct statements are (ii), (iii), and (iv) — ozone is toxic in nature but beneficial at higher altitudes because it shields the Earth from UV rays. Hence, the ozone layer is crucial for maintaining life on Earth. The correct option is (B).

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  5. In the given cross, a black-furred rabbit (B) is dominant, and a white-furred rabbit (b) is recessive. When a pure black rabbit (BB) is crossed with a pure white rabbit (bb), the F₁ generation gets the genotype Bb. All offspring appear black since the dominant gene masks the recessive one. Hence, thRead more

    In the given cross, a black-furred rabbit (B) is dominant, and a white-furred rabbit (b) is recessive. When a pure black rabbit (BB) is crossed with a pure white rabbit (bb), the F₁ generation gets the genotype Bb. All offspring appear black since the dominant gene masks the recessive one. Hence, the correct parental cross is BB × bb, producing all black (Bb) rabbits in the F₁ generation due to dominance of the black fur gene. The correct option is (A).

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