Class 10 Science Our Environment MCQS

1️⃣ Which of the following is a non-biodegradable waste? 🗑️

  • A. Vegetable peels
  • B. Paper
  • C. Plastic
  • D. Cotton cloth
Show Answer 🔽

C. Plastic

2️⃣ The ozone layer is important because it: ☁️

  • A. Protects from UV radiation
  • B. Absorbs carbon dioxide
  • C. Produces oxygen
  • D. Traps greenhouse gases
Show Answer 🔽

A. Protects from UV radiation

3️⃣ Which gas is responsible for ozone layer depletion? 🧪

  • A. Carbon dioxide
  • B. Methane
  • C. Chlorofluorocarbons (CFCs)
  • D. Oxygen
Show Answer 🔽

C. Chlorofluorocarbons (CFCs)

4️⃣ Which of the following organisms is always at the first trophic level? 🌿

  • A. Carnivores
  • B. Herbivores
  • C. Omnivores
  • D. Producers
Show Answer 🔽

D. Producers

5️⃣ The decomposers in an ecosystem include: 🍄

  • A. Plants
  • B. Bacteria and fungi
  • C. Herbivores
  • D. Carnivores
Show Answer 🔽

B. Bacteria and fungi

6️⃣ Energy flow in an ecosystem is: 🔁

  • A. Cyclic
  • B. Random
  • C. Unidirectional
  • D. Irregular
Show Answer 🔽

C. Unidirectional

7️⃣ Which is the correct sequence in a food chain? 🍽️

  • A. Carnivores → Herbivores → Producers
  • B. Producers → Herbivores → Carnivores
  • C. Herbivores → Producers → Carnivores
  • D. Decomposers → Carnivores → Producers
Show Answer 🔽

B. Producers → Herbivores → Carnivores

8️⃣ Which of these is a biodegradable material? ♻️

  • A. Glass
  • B. Plastic bag
  • C. Aluminum foil
  • D. Cotton
Show Answer 🔽

D. Cotton

9️⃣ Greenhouse effect is caused by: 🌡️

  • A. Oxygen
  • B. Nitrogen
  • C. Greenhouse gases
  • D. Hydrogen
Show Answer 🔽

C. Greenhouse gases

🔟 Food web is: 🕸️

  • A. Linear chain of food
  • B. Interconnected food chains
  • C. Only herbivores and carnivores
  • D. Only producers and consumers
Show Answer 🔽

B. Interconnected food chains

1️⃣1️⃣ Which of the following is a greenhouse gas? 🌫️ (PYQ)

  • A. Nitrogen
  • B. Oxygen
  • C. Carbon dioxide
  • D. Hydrogen
Show Answer 🔽

C. Carbon dioxide

1️⃣2️⃣ What will happen if all decomposers are eliminated from the Earth? 🌍 (PYQ)

  • A. Herbivore population increases
  • B. Dead matter accumulates
  • C. More oxygen is produced
  • D. Carnivores vanish
Show Answer 🔽

B. Dead matter accumulates

1️⃣3️⃣ Which of the following is the best method to dispose of kitchen waste? 🍽️

  • A. Incineration
  • B. Composting
  • C. Landfilling
  • D. Dumping in water bodies
Show Answer 🔽

B. Composting

1️⃣4️⃣ Which of these is not part of a food chain? ❌

  • A. Producer
  • B. Herbivore
  • C. Decomposer
  • D. Fossil fuel
Show Answer 🔽

D. Fossil fuel

1️⃣5️⃣ Trophic levels represent: 📊

  • A. Steps in food chain
  • B. Types of plants
  • C. Number of species
  • D. Biodegradable waste
Show Answer 🔽

A. Steps in food chain

1️⃣6️⃣ Which of the following is not biodegradable? 🚫

  • A. Animal bones
  • B. Wool
  • C. Polythene
  • D. Tea leaves
Show Answer 🔽

C. Polythene

1️⃣7️⃣ How much energy is transferred from one trophic level to the next? 🔄 (PYQ)

  • A. 100%
  • B. 50%
  • C. 10%
  • D. 1%
Show Answer 🔽

C. 10%

1️⃣8️⃣ The most harmful effect of CFCs is: 🧪

  • A. Global warming
  • B. Water pollution
  • C. Ozone depletion
  • D. Acid rain
Show Answer 🔽

C. Ozone depletion

1️⃣9️⃣ Which of the following is a correct food chain? 🔗

  • A. Plants → Deer → Lion
  • B. Lion → Plants → Deer
  • C. Deer → Lion → Plants
  • D. Lion → Deer → Plants
Show Answer 🔽

A. Plants → Deer → Lion

2️⃣0️⃣ Which organism feeds on both plants and animals? 🍔

  • A. Herbivore
  • B. Carnivore
  • C. Omnivore
  • D. Decomposer
Show Answer 🔽

C. Omnivore

2️⃣1️⃣ Which of the following contributes to acid rain? 🌧️

  • A. Ozone
  • B. Sulphur dioxide
  • C. Nitrogen gas
  • D. Hydrogen
Show Answer 🔽

B. Sulphur dioxide

2️⃣2️⃣ Which human activity is responsible for ozone layer depletion? 🧼 (PYQ)

  • A. Use of pesticides
  • B. Use of CFC-based coolants
  • C. Industrial noise
  • D. Mining
Show Answer 🔽

B. Use of CFC-based coolants

2️⃣3️⃣ In a food chain, energy is lost as: 🔥

  • A. Heat
  • B. Sound
  • C. Movement
  • D. Light
Show Answer 🔽

A. Heat

2️⃣4️⃣ The term “biomagnification” refers to: 📈

  • A. Accumulation of food
  • B. Accumulation of toxic chemicals
  • C. Growth of population
  • D. Increase in biodiversity
Show Answer 🔽

B. Accumulation of toxic chemicals

2️⃣5️⃣ The primary source of energy in an ecosystem is: ☀️ (PYQ)

  • A. Plants
  • B. Water
  • C. Sun
  • D. Soil
Show Answer 🔽

C. Sun

2️⃣6️⃣ What is the role of decomposers? 🔄

  • A. Eat producers
  • B. Eat herbivores
  • C. Convert organic waste to simpler substances
  • D. Make food
Show Answer 🔽

C. Convert organic waste to simpler substances

2️⃣7️⃣ Which one is a non-renewable resource? ⛽

  • A. Water
  • B. Wind
  • C. Sunlight
  • D. Petroleum
Show Answer 🔽

D. Petroleum

2️⃣8️⃣ Which of the following would increase the size of the ozone hole? 🧊

  • A. Increase in oxygen
  • B. Increased use of plastics
  • C. Increased use of CFCs
  • D. Decrease in nitrogen
Show Answer 🔽

C. Increased use of CFCs

2️⃣9️⃣ The final trophic level in a food chain is generally occupied by: 🦁

  • A. Herbivores
  • B. Decomposers
  • C. Producers
  • D. Top carnivores
Show Answer 🔽

D. Top carnivores

3️⃣0️⃣ Ozone is a molecule made of: ⚗️

  • A. One oxygen atom
  • B. Two oxygen atoms
  • C. Three oxygen atoms
  • D. Four oxygen atoms
Show Answer 🔽

C. Three oxygen atoms

3️⃣1️⃣ Which organism can be at both second and third trophic levels? 🐒

  • A. Lion
  • B. Cow
  • C. Human
  • D. Snake
Show Answer 🔽

C. Human

3️⃣2️⃣ The major cause of the greenhouse effect is: 🌍

  • A. High oxygen levels
  • B. Increase in UV rays
  • C. Emission of CO₂ and methane
  • D. Acid rain
Show Answer 🔽

C. Emission of CO₂ and methane

3️⃣3️⃣ Ozone layer is present in: ☁️

  • A. Troposphere
  • B. Mesosphere
  • C. Stratosphere
  • D. Exosphere
Show Answer 🔽

C. Stratosphere

3️⃣4️⃣ Which group contains only biodegradable items? ♻️ (PYQ)

  • A. Plastic, paper, fruit peels
  • B. Cotton, wool, leather
  • C. Paper, plastic, wood
  • D. Polythene, bones, wool
Show Answer 🔽

B. Cotton, wool, leather

3️⃣5️⃣ Which of the following is most harmful for the environment? ❌

  • A. Paper bags
  • B. Jute bags
  • C. Cloth bags
  • D. Plastic bags
Show Answer 🔽

D. Plastic bags

3️⃣6️⃣ If all herbivores are removed from the ecosystem, it will affect: 🌱🐄

  • A. Only carnivores
  • B. Only decomposers
  • C. Producers and carnivores
  • D. None
Show Answer 🔽

C. Producers and carnivores

3️⃣7️⃣ Energy flow in a food chain is governed by: 💡 (PYQ)

  • A. 20% Law
  • B. 90% Law
  • C. 10% Law
  • D. Law of inertia
Show Answer 🔽

C. 10% Law

3️⃣8️⃣ Biodegradable waste can be broken down by: 🔬

  • A. Physical processes
  • B. Sunlight
  • C. Microorganisms
  • D. Machines
Show Answer 🔽

C. Microorganisms

3️⃣9️⃣ Which of the following is a secondary consumer? 🐍

  • A. Grass
  • B. Cow
  • C. Snake
  • D. Frog
Show Answer 🔽

C. Snake

4️⃣0️⃣ Which of these human activities has caused maximum damage to the environment? 🏭

  • A. Using CNG
  • B. Using LED bulbs
  • C. Burning fossil fuels
  • D. Installing solar panels
Show Answer 🔽

C. Burning fossil fuels

4️⃣1️⃣ Which statement is true about food chains? 🔗

  • A. They are always straight
  • B. They always start with consumers
  • C. They start with producers and flow toward top consumers
  • D. Decomposers are always in the middle
Show Answer 🔽

C. They start with producers and flow toward top consumers

4️⃣2️⃣ Which of the following will not reduce waste production? 🚯

  • A. Recycling
  • B. Composting
  • C. Reusing
  • D. Dumping in rivers
Show Answer 🔽

D. Dumping in rivers

4️⃣3️⃣ The maximum energy is available at which trophic level? 🔋

  • A. Producer
  • B. Herbivore
  • C. Carnivore
  • D. Decomposer
Show Answer 🔽

A. Producer

4️⃣4️⃣ What causes biological magnification in a food chain? 🧬 (PYQ)

  • A. Oxygen
  • B. CO₂
  • C. Harmful chemicals
  • D. Nitrogen
Show Answer 🔽

C. Harmful chemicals

4️⃣5️⃣ An eco-friendly activity among the following is: 🌿

  • A. Using plastic straws
  • B. Burning leaves
  • C. Using paper bags
  • D. Throwing garbage in open
Show Answer 🔽

C. Using paper bags

4️⃣6️⃣ What is the role of sunlight in an ecosystem? ☀️

  • A. Maintains temperature
  • B. Powers decomposers
  • C. Initiates photosynthesis
  • D. Causes pollution
Show Answer 🔽

C. Initiates photosynthesis

4️⃣7️⃣ Which among these is a non-greenhouse gas? ❄️

  • A. Carbon dioxide
  • B. Methane
  • C. Nitrous oxide
  • D. Oxygen
Show Answer 🔽

D. Oxygen

4️⃣8️⃣ What is the main component of biogas? 🔥

  • A. Methane
  • B. Carbon monoxide
  • C. Oxygen
  • D. Hydrogen
Show Answer 🔽

A. Methane

4️⃣9️⃣ The amount of energy transferred from one level to next is only: ⚡

  • A. 100%
  • B. 10%
  • C. 50%
  • D. 25%
Show Answer 🔽

B. 10%

5️⃣0️⃣ Which component is not part of a natural ecosystem? 🌲

  • A. Air
  • B. Water
  • C. Buildings
  • D. Plants
Show Answer 🔽

C. Buildings

5️⃣1️⃣ Which of the following organisms help in cleaning the environment? 🧹

  • A. Lions
  • B. Cows
  • C. Decomposers
  • D. Elephants
Show Answer 🔽

C. Decomposers

5️⃣2️⃣ Which of the following pollutants is mainly responsible for ozone depletion? ☠️

  • A. CO₂
  • B. SO₂
  • C. CFCs
  • D. NO₂
Show Answer 🔽

C. CFCs

5️⃣3️⃣ What is the main function of producers in an ecosystem? 🌱

  • A. Decompose waste
  • B. Eat other animals
  • C. Make food using sunlight
  • D. Absorb CO₂
Show Answer 🔽

C. Make food using sunlight

5️⃣4️⃣ Which of these is NOT a greenhouse gas? 💨

  • A. Methane
  • B. Carbon dioxide
  • C. Oxygen
  • D. Nitrous oxide
Show Answer 🔽

C. Oxygen

5️⃣5️⃣ A food chain always begins with: 🌞 (PYQ)

  • A. Herbivores
  • B. Decomposers
  • C. Carnivores
  • D. Producers
Show Answer 🔽

D. Producers

5️⃣6️⃣ What will happen if we remove decomposers from the environment? 🧫

  • A. More biodiversity
  • B. No photosynthesis
  • C. Waste will pile up
  • D. More food chains form
Show Answer 🔽

C. Waste will pile up

5️⃣7️⃣ An example of a primary consumer is: 🐄

  • A. Lion
  • B. Goat
  • C. Eagle
  • D. Snake
Show Answer 🔽

B. Goat

5️⃣8️⃣ Which of the following shows correct energy flow in a food chain? 🔁

  • A. Carnivores → Herbivores → Producers
  • B. Producers → Herbivores → Carnivores
  • C. Herbivores → Producers → Carnivores
  • D. Decomposers → Herbivores → Producers
Show Answer 🔽

B. Producers → Herbivores → Carnivores

5️⃣9️⃣ Which level of consumers directly depends on producers for food? 🌿

  • A. Secondary consumers
  • B. Primary consumers
  • C. Tertiary consumers
  • D. Apex consumers
Show Answer 🔽

B. Primary consumers

6️⃣0️⃣ The ozone layer protects us from: ☀️ (PYQ)

  • A. Gamma rays
  • B. X-rays
  • C. Infrared rays
  • D. Ultraviolet rays
Show Answer 🔽

D. Ultraviolet rays

6️⃣1️⃣ The main source of CFCs is: ❄️

  • A. Cooking gas
  • B. Air conditioners and refrigerators
  • C. Fertilizers
  • D. Plastic bottles
Show Answer 🔽

B. Air conditioners and refrigerators

6️⃣2️⃣ What is meant by a food web? 🕸️

  • A. Only linear food chains
  • B. All consumers feeding on the same plant
  • C. Interconnected food chains
  • D. Carnivores eating herbivores only
Show Answer 🔽

C. Interconnected food chains

6️⃣3️⃣ Which of these is the cleanest source of energy? 💡

  • A. Petroleum
  • B. Coal
  • C. Wind
  • D. Diesel
Show Answer 🔽

C. Wind

6️⃣4️⃣ Which part of the food chain gets the least energy? 📉

  • A. Producers
  • B. Primary consumers
  • C. Secondary consumers
  • D. Tertiary consumers
Show Answer 🔽

D. Tertiary consumers

6️⃣5️⃣ Which type of waste takes the longest time to decompose? 🕒

  • A. Food scraps
  • B. Paper
  • C. Cotton
  • D. Plastic
Show Answer 🔽

D. Plastic

6️⃣6️⃣ Which of these is the last link in a food chain? 🔗

  • A. Producer
  • B. Consumer
  • C. Decomposer
  • D. Omnivore
Show Answer 🔽

C. Decomposer

6️⃣7️⃣ In biological magnification, harmful chemicals:

  • A. Decrease at each level
  • B. Get diluted
  • C. Accumulate more at higher levels
  • D. Stay the same
Show Answer 🔽

C. Accumulate more at higher levels

6️⃣8️⃣ Which is the most eco-friendly practice? ♻️

  • A. Burning plastic
  • B. Using one-time disposables
  • C. Carrying cloth bags
  • D. Using fossil fuels
Show Answer 🔽

C. Carrying cloth bags

6️⃣9️⃣ Which activity will reduce the size of your carbon footprint? 👣

  • A. Using diesel cars
  • B. Cycling to school
  • C. Using plastic bags
  • D. Eating packaged food
Show Answer 🔽

B. Cycling to school

7️⃣0️⃣ What type of resource is sunlight? ☀️

  • A. Renewable
  • B. Non-renewable
  • C. Artificial
  • D. Exhaustible
Show Answer 🔽

A. Renewable

7️⃣1️⃣ Which human activity contributes the most to global warming? 🌡️

  • A. Planting trees
  • B. Using solar energy
  • C. Burning fossil fuels
  • D. Using windmills
Show Answer 🔽

C. Burning fossil fuels

7️⃣2️⃣ What is the correct sequence of energy flow in an ecosystem? 🔁

  • A. Sun → Carnivore → Herbivore → Producer
  • B. Sun → Producer → Herbivore → Carnivore
  • C. Producer → Sun → Herbivore → Carnivore
  • D. Carnivore → Producer → Sun → Herbivore
Show Answer 🔽

B. Sun → Producer → Herbivore → Carnivore

7️⃣3️⃣ Which of the following is a renewable resource? ♻️

  • A. Petroleum
  • B. Natural gas
  • C. Wind
  • D. Coal
Show Answer 🔽

C. Wind

7️⃣4️⃣ Which of the following is a threat to biodiversity? 🐘

  • A. Wildlife conservation
  • B. Reforestation
  • C. Habitat destruction
  • D. Ecotourism
Show Answer 🔽

C. Habitat destruction

7️⃣5️⃣ Which process is responsible for the conversion of dead organisms to nutrients? 🌿

  • A. Respiration
  • B. Photosynthesis
  • C. Decomposition
  • D. Fermentation
Show Answer 🔽

C. Decomposition

7️⃣6️⃣ Why is energy flow in an ecosystem unidirectional? ➡️

  • A. Because energy is recycled
  • B. Due to sunlight loss
  • C. Energy is lost as heat at each level
  • D. Trophic levels are circular
Show Answer 🔽

C. Energy is lost as heat at each level

7️⃣7️⃣ The term ‘biodegradable’ refers to substances that: 🧪

  • A. Cannot be broken down
  • B. Are toxic to animals
  • C. Can be broken down by microorganisms
  • D. Are not part of ecosystem
Show Answer 🔽

C. Can be broken down by microorganisms

7️⃣8️⃣ Which of the following is an abiotic component of an ecosystem? ⛰️

  • A. Bacteria
  • B. Plants
  • C. Animals
  • D. Temperature
Show Answer 🔽

D. Temperature

7️⃣9️⃣ Which of the following contributes to water pollution? 🚱

  • A. Reuse of grey water
  • B. Industrial waste discharge
  • C. Rain harvesting
  • D. Wastewater treatment
Show Answer 🔽

B. Industrial waste discharge

8️⃣0️⃣ The largest amount of energy in a food pyramid is available at: 🔺 (PYQ)

  • A. Top carnivore level
  • B. Herbivore level
  • C. Producer level
  • D. Omnivore level
Show Answer 🔽

C. Producer level

8️⃣1️⃣ Which human action does NOT harm the environment? ✅

  • A. Deforestation
  • B. Reforestation
  • C. Industrial waste dumping
  • D. Fossil fuel burning
Show Answer 🔽

B. Reforestation

8️⃣2️⃣ Which of the following breaks down waste in composting? 🍃

  • A. Light
  • B. Oxygen only
  • C. Bacteria and fungi
  • D. Earthworms only
Show Answer 🔽

C. Bacteria and fungi

8️⃣3️⃣ Which of these is NOT a consequence of global warming? 🌎

  • A. Melting glaciers
  • B. Rising sea levels
  • C. Increase in rainfall
  • D. Decreased atmospheric CO₂
Show Answer 🔽

D. Decreased atmospheric CO₂

8️⃣4️⃣ The gas primarily responsible for acid rain is: 🌧️

  • A. Oxygen
  • B. Sulphur dioxide
  • C. Methane
  • D. Ozone
Show Answer 🔽

B. Sulphur dioxide

8️⃣5️⃣ Biodegradable waste includes: 🍎

  • A. Plastic bottles
  • B. Glass jars
  • C. Vegetable peels
  • D. Aluminium foil
Show Answer 🔽

C. Vegetable peels

8️⃣6️⃣ An increase in which gas causes the greenhouse effect? 🌫️

  • A. Nitrogen
  • B. Oxygen
  • C. Carbon dioxide
  • D. Hydrogen
Show Answer 🔽

C. Carbon dioxide

8️⃣7️⃣ Which is NOT a biodegradable item? ❌

  • A. Banana peel
  • B. Old newspaper
  • C. Polythene bag
  • D. Eggshell
Show Answer 🔽

C. Polythene bag

8️⃣8️⃣ The best way to manage organic kitchen waste is: 🥦

  • A. Burning
  • B. Composting
  • C. Landfilling
  • D. Dumping in rivers
Show Answer 🔽

B. Composting

8️⃣9️⃣ Which of the following practices helps conserve the environment? 🌿

  • A. Overuse of pesticides
  • B. Throwing plastic in open
  • C. Rainwater harvesting
  • D. Cutting down trees
Show Answer 🔽

C. Rainwater harvesting

9️⃣0️⃣ A stable ecosystem is one where: ⚖️

  • A. Energy is reused
  • B. There is only one food chain
  • C. Species interact and maintain balance
  • D. No decomposers are present
Show Answer 🔽

C. Species interact and maintain balance

9️⃣1️⃣ Which of the following helps reduce soil pollution? 🌱

  • A. Using chemical fertilizers
  • B. Burning plastic
  • C. Practicing organic farming
  • D. Dumping e-waste
Show Answer 🔽

C. Practicing organic farming

9️⃣2️⃣ The correct order of food chain is: 📊

  • A. Herbivore → Producer → Carnivore
  • B. Producer → Carnivore → Herbivore
  • C. Producer → Herbivore → Carnivore
  • D. Carnivore → Herbivore → Producer
Show Answer 🔽

C. Producer → Herbivore → Carnivore

9️⃣3️⃣ What is one main cause of water pollution? 💧

  • A. Composting
  • B. Industrial discharge
  • C. Solar energy
  • D. Reforestation
Show Answer 🔽

B. Industrial discharge

9️⃣4️⃣ The largest food chain contributor is: 🌾

  • A. Animals
  • B. Humans
  • C. Plants
  • D. Fungi
Show Answer 🔽

C. Plants

9️⃣5️⃣ What is the effect of biomagnification on top consumers? 🐆

  • A. They get stronger
  • B. No effect
  • C. Accumulate maximum toxins
  • D. Die due to starvation
Show Answer 🔽

C. Accumulate maximum toxins

9️⃣6️⃣ Why is plastic harmful to the environment? ♨️

  • A. It evaporates easily
  • B. It is 100% biodegradable
  • C. It stays in the environment for years
  • D. It increases oxygen content
Show Answer 🔽

C. It stays in the environment for years

9️⃣7️⃣ Which of the following helps control global warming? 🌍

  • A. Using more plastic
  • B. Afforestation
  • C. Burning coal
  • D. Using diesel cars
Show Answer 🔽

B. Afforestation

9️⃣8️⃣ What type of ecosystem is a pond? 🐟

  • A. Natural
  • B. Artificial
  • C. Terrestrial
  • D. Desert
Show Answer 🔽

A. Natural

9️⃣9️⃣ What is the main cause of ozone hole formation? 🕳️

  • A. Burning wood
  • B. UV rays
  • C. Chlorofluorocarbons
  • D. CO₂ emissions
Show Answer 🔽

C. Chlorofluorocarbons

1️⃣0️⃣0️⃣ Which of the following is a major non-biodegradable pollutant? 🛍️

  • A. Fruit peel
  • B. Paper
  • C. Cotton
  • D. Plastic
Show Answer 🔽

D. Plastic

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