Our Environment — Class 10 MCQs with Answers
Class 10 CBSE Science · Chapter 13
90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated
Practise the most important Class 10 CBSE Science questions from Chapter 13, "Our Environment". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE Board exams and the JEE & NEET foundation years apart.
To score well in "Our Environment", focus on clear concepts in physics, chemistry and biology basics. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Our Environment, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 10 Science mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Our Environment (Class 10 Science)
Living organisms and their surroundings form ecosystems in which energy flows one way and matter is recycled. This chapter covers food chains and trophic levels, the accumulation of harmful chemicals, and the two environmental problems of ozone depletion and waste management.
- Ecosystem
- A unit made of all the organisms in an area together with their non-living surroundings, interacting as a system.
- Biotic and abiotic components
- Biotic components are the living organisms; abiotic components are physical factors such as light, temperature, water and soil.
- Producers
- Green plants and some bacteria that make their own food by photosynthesis and support every other organism in the ecosystem.
- Consumers
- Organisms that depend on others for food, classed as herbivores, carnivores, omnivores and parasites.
Our Environment — important questions & MCQs with answers (Class 10 Science)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.
- Q1Easy
In a food chain, plants are:
A.PredatorsB.ConsumersC.DecomposersD.Producers✓ CorrectAnswer: D. Producers
Explanation: Plants make their own food via photosynthesis, so they occupy the producer level of a food chain — unlike consumers, which must eat other organisms for energy.
- Q2Easy
Ozone layer protects us from:
A.Ultraviolet (UV) radiation✓ CorrectB.Cosmic raysC.Visible lightD.HeatAnswer: A. Ultraviolet (UV) radiation
Explanation: Ozone (O₃) in the stratosphere absorbs most incoming ultraviolet radiation, shielding living cells from UV-induced DNA damage; it does not block cosmic rays or visible light.
- Q3Easy
Green plants in a food chain are:
A.DecomposersB.ConsumersC.Producers✓ CorrectD.PredatorsAnswer: C. Producers
Explanation: Green plants synthesise their own food through photosynthesis, making them producers that form the first trophic level of every food chain.
- Q4Easy
A food web is:
A.Single food chainB.Network of interconnected food chains✓ CorrectC.Pyramid of numbersD.Pyramid of energyAnswer: B. Network of interconnected food chains
Explanation: A food web is a network of many interlinked food chains, since most organisms eat and are eaten by more than one species — unlike a single straight-line food chain.
- Q5Easy
Ozone layer in the upper atmosphere protects us from:
A.Cosmic dustB.Visible lightC.HeatD.Harmful UV radiation✓ CorrectAnswer: D. Harmful UV radiation
Explanation: The stratospheric ozone layer absorbs harmful ultraviolet radiation (mainly UV-B and UV-C) before it reaches the surface, preventing damage to living cells.
- Q6Easy
Biodegradable wastes include:
A.Vegetable peels, paper, cotton✓ CorrectB.PlasticC.GlassD.AluminiumAnswer: A. Vegetable peels, paper, cotton
Explanation: Vegetable peels, paper and cotton are made of organic material that microorganisms can decompose; plastic, glass and aluminium are synthetic or inorganic and resist breakdown.
- Q7Medium
According to the 10% law, energy passed to next trophic level is:
A.100%B.1%C.50%D.10%✓ CorrectAnswer: D. 10%
Explanation: The 10% law (Lindeman) states only about 10% of energy at one trophic level is passed to the next — the remaining ~90% is lost as heat during respiration and other life processes.
- Q8Medium
Which is biodegradable?
A.PlasticB.Vegetable peels✓ CorrectC.GlassD.Aluminium foilAnswer: B. Vegetable peels
Explanation: Vegetable peels are organic matter that microbes can break down (biodegradable); plastic, glass and aluminium foil resist microbial decomposition and persist for years.
- Q9Medium
In the food chain: grass → grasshopper → frog → snake, the snake is at:
A.DecomposerB.ProducerC.Primary consumerD.Quaternary or tertiary consumer level✓ CorrectAnswer: D. Quaternary or tertiary consumer level
Explanation: The snake feeds on the frog and is eaten by nothing else here, so it sits at the top as a tertiary/quaternary consumer.
- Q10Medium
When each organism is eaten by two or more kinds of organisms, the relationships form a:
A.Straight food chainB.Trophic pyramidC.Food web✓ CorrectD.Single nicheAnswer: C. Food web
Explanation: Instead of a straight line food chain, the relationship can be shown as a series of branching lines called a food web.
- Q11Medium
UV radiation can cause:
A.Increased crop yieldB.Better skinC.Skin cancer and eye damage✓ CorrectD.Cooling of EarthAnswer: C. Skin cancer and eye damage
Explanation: UV radiation damages DNA in living cells, leading to skin cancer and eye damage.
- Q12Hard
Decomposers in an ecosystem are mainly:
A.PlantsB.HerbivoresC.Bacteria and fungi✓ CorrectD.CarnivoresAnswer: C. Bacteria and fungi
Explanation: Bacteria and fungi secrete enzymes that break down dead organic matter into simpler substances, releasing nutrients back into the soil — a role plants and animals don't perform.
- Q13Hard
Ozone layer depletion is caused by:
A.CO₂B.N₂C.O₂D.CFCs (chlorofluorocarbons)✓ CorrectAnswer: D. CFCs (chlorofluorocarbons)
Explanation: Chlorofluorocarbons (CFCs) released from aerosols and refrigerants rise to the stratosphere, where UV light frees chlorine atoms that catalytically break down ozone molecules.
- Q14Hard
In a grassland ecosystem, the correct order of trophic levels is:
A.Grass → eagle → snakeB.Grass → grasshopper → frog → snake → eagle✓ CorrectC.Reverse of typicalD.RandomAnswer: B. Grass → grasshopper → frog → snake → eagle
Explanation: Each organism must be eaten by the next: grass (producer) → grasshopper (herbivore) → frog (eats grasshopper) → snake (eats frog) → eagle (top predator), in that fixed order.
Start this chapter free
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This chapter has 90 questions (30 Easy · 30 Medium · 30 Hard), with timed scoring and instant feedback. The rest unlock with the ₹999/year plan.
Start this chapter free →Our Environment — FAQs
What are the key concepts in Class 10 Science Our Environment?+
Living organisms and their surroundings form ecosystems in which energy flows one way and matter is recycled. This chapter covers food chains and trophic levels, the accumulation of harmful chemicals, and the two environmental problems of ozone depletion and waste management. Key ideas include Ecosystem, Biotic and abiotic components, Producers, Consumers.
What does Class 10 Science Chapter 13 (Our Environment) cover on XamBaaz?+
It has 90 NCERT-based MCQs on "Our Environment": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE Board exams and the JEE & NEET foundation years.
Are these "Our Environment" questions free to practise?+
Yes. Sign in with Google to practise "Our Environment" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Our Environment" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Our Environment" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Our Environment" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Our Environment (Class 10 Science)?+
The questions that matter most test Ecosystem, Biotic and abiotic components, Producers, Consumers. This page shows 14 solved important MCQs with answers and explanations; all 90 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Our Environment?+
Yes — Class 10 Science Our Environment has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.