When dilute HCl reacts with zinc granules, bubbles of hydrogen gas are released, showing effervescence. Also, zinc chloride solution forms. These two observable changes confirm that a new substance is formed, proving chemical change. class 10 science half yearly 2025 cbse class ...
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A is true but R is false. Biodegradable substances like food waste or leaves decompose into simpler organic matter, forming compost and replenishing soil. The reason is false, as it mentions inorganic substances instead of organic substances. Assertion is ...
A is true but R is false. When current increases in a conductor, the magnetic field becomes stronger. This causes a greater deflection of the compass needle, not a decrease. Thus, assertion is false, while the reason is scientifically ...
Both A and R are true, and R is the correct explanation of A. Sexual reproduction introduces genetic variations, increasing adaptability to environmental changes. These variations give better chances of survival compared to asexual reproduction. Hence, both assertion and reason ...
The correct answer is [A] (ii) and (iv).‘A’ represents the diaphragm. During inhalation, it flattens and helps the chest cavity to become larger, allowing air to enter the lungs. It doesn’t decrease residual volume.