Subject Knowledge

Biodegradable substances are those that can be naturally decomposed and broken down by biological agents such as bacteria and fungi. Option A is incorrect because materials that resist organic breakdown are classified as non-biodegradable, which often leads to environmental pollution.

Kendriya Vidyalayas are central government schools affiliated with the Central Board of Secondary Education (CBSE) to ensure a standardized national curriculum. State Boards (Option A) are incorrect because they govern regional state schools rather than this central school system.

Kendriya Vidyalayas are central government schools affiliated with the Central Board of Secondary Education (CBSE) to ensure a standardized national curriculum. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !State Boards (Option A) are incorrect because they govern regional state schools rather than this central school system.
• !Option A is incorrect because zero is classified as a whole number, rather than a natural counting number.
• !Option A is incorrect because Sydney, while being the country's most populous city, is actually the state capital of New South Wales.
• !Option A is incorrect because materials that resist organic breakdown are classified as non-biodegradable, which often leads to environmental pollution.
• !Option D is incorrect because water only reaches boiling points above 100 °C under higher pressure, such as inside a pressure cooker.

Answer each from memory — you'll see instantly whether you're right and why.

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