Our Environment

CBSE Class 10 Science · every board question from this chapter, 2025–2025 · 16 of them repeated across years

• The examples of natural and manmade (artificial) ecosystems are respectively2025asked 3×
• Which of the following groups do not constitute a food chain? (i) Wolf, rabbit, grass, lion (ii) Plankton, man, grasshopper, fish…2025asked 3×
• In the following groups of wastes, which group contains only non- biodegradable wastes?2025
• Consider the following food chain: Grass → Grasshopper → Frog → Snake → Eagle If the amount of energy available at third trophic…2025asked 2×
• In the food chains given below. Select the most efficient food chain in terms of energy:2025asked 3×
• Other than the abiotic components, which of the given biotic components are not required to make an aquarium with small…2025asked 3×
• Which one of the following gets biomagnified at different levels in a food chain?2025asked 3×
• Identify from the following a group containing all non-biodegradable substances.2025asked 3×
• The incorrect statement about ozone is2025asked 2×
• Green plants occupy the first trophic level in every food chain because they2025
• Human activities that are affecting the environment are:2025asked 3×
• Assertion: The amount of ozone in the atmosphere began to drop sharply in the 1980s. Reason (R): The oxygen atoms combine with…2025asked 3×
• Assertion: Use of jute bags for shopping reduces pollution. Reason (R): Jute is biodegradable and its bag may be reused as and…2025asked 3×
• Assertion: Food web is a network of several food chains operating in an ecosystem. Reason (R): Food web decreases the stability…2025asked 3×
• A gas 'X' is found in the upper layer of atmosphere. It is a deadly poison, but still essential for all life forms on earth.…2025
• Study the food web given below: Identify the food chain(s) in which the eagle receives the highest energy from the producers.…2025
• Why are the organisms of first trophic level important in any food chain? Justify the following statement: 'The flow of energy in…2025
• "Excessive use of chemicals and pesticides in agriculture adversely effect the environment." Justify this statement.2025asked 2×
• Indicate the flow of energy in a food chain operating in an ecosystem. Why is it uni-directional? Give reason.2025
• We do not clean natural ponds or lakes whereas an aquarium or a swimming pool needs to be cleaned regularly. Why?2025
• Some harmful chemicals get accumulated in human bodies through the food chain. Name this phenomenon. Explain the reason of…2025
• Write the essential function performed by ozone at the higher levels of the atmosphere. How is it formed in the upper atmosphere?…2025asked 2×
• "In a food chain energy flow is unidirectional." Give two reasons for the given statement. If 10,000 J energy is available at the…2025asked 3×
• What are decomposers? Give two examples. State how they maintain a balance in an ecosystem.2025asked 3×

Answers come from CBSE’s own marking schemes. How we source them.