Our Environment (Class 10 Science)

Our environment consists of living and non-living components that interact with each other. Understanding environmental ecosystems and food chains helps us

Our Environment (Class 10 Science)

Our environment consists of living and non-living components that interact with each other. Understanding environmental ecosystems and food chains helps us

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TL;DR: Our environment consists of living and non-living components that interact with each other. Understanding environmental ecosystems and food chains hel…

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Our environment consists of living and non-living components that interact with each other. Understanding environmental ecosystems and food chains helps us

Our Environment MCQs with Answers & Explanations

Q1. What is an ecosystem?

  1. Living organisms and their physical environment in an area ✓ (correct)
  2. Only animals in an area
  3. Only plants in an area
  4. Only soil

Explanation: An ecosystem includes all living organisms (biotic) and non-living things (abiotic) in an area, along with their interactions.

Q2. What are producers in an ecosystem?

  1. Animals that eat plants
  2. Green plants that make their own food ✓ (correct)
  3. Organisms that decompose
  4. Humans

Explanation: Producers are autotrophs, mainly green plants, that produce food through photosynthesis using sunlight.

Q3. What are decomposers in an ecosystem?

  1. Herbivores
  2. Parasites
  3. Organisms that break down dead organic matter ✓ (correct)
  4. Carnivores

Explanation: Decomposers like bacteria and fungi break down dead organic matter and release nutrients back into the soil.

Q4. What is a food chain?

  1. A chain of restaurants
  2. A type of food
  3. A line of animals
  4. A sequence showing energy transfer from producers to consumers ✓ (correct)

Explanation: A food chain is a linear sequence showing the transfer of energy from producers through various levels of consumers.

Q5. What percentage of energy is transferred from one trophic level to the next?

  1. 10% ✓ (correct)
  2. 25%
  3. 100%
  4. 50%

Explanation: Approximately 10% of energy is transferred from one trophic level to the next, with the rest lost as heat and in metabolism.

Q6. What is biomagnification?

  1. Increase in organism size
  2. Accumulation of toxic substances in higher trophic levels ✓ (correct)
  3. Growth of biomass
  4. Increase in food chain length

Explanation: Biomagnification is the accumulation of harmful substances like pesticides in organisms at higher trophic levels in greater concentrations.

Q7. What is the main cause of ozone layer depletion?

  1. Nitrogen oxides
  2. Carbon dioxide
  3. Chlorofluorocarbons (CFCs) ✓ (correct)
  4. Methane

Explanation: CFCs are chlorine-containing compounds that break down ozone molecules in the stratosphere, creating the ozone hole.

Q8. What is the greenhouse effect?

  1. Growing plants in a greenhouse
  2. Acid rain
  3. Depletion of ozone
  4. Trapping of heat in the atmosphere by gases ✓ (correct)

Explanation: The greenhouse effect is the warming of Earth's atmosphere due to infrared radiation being trapped by gases like CO2 and methane.

Q9. Which gas is primarily responsible for global warming?

  1. Carbon dioxide ✓ (correct)
  2. Argon
  3. Oxygen
  4. Nitrogen

Explanation: Carbon dioxide is the major greenhouse gas contributing to global warming, released mainly by burning fossil fuels.

Q10. What is waste management?

  1. Burning waste
  2. Minimize waste and dispose responsibly through reduce, reuse, recycle ✓ (correct)
  3. Throwing waste away
  4. Burying waste

Explanation: Waste management involves reducing waste generation, reusing materials, and recycling to minimize environmental impact.

Frequently Asked Questions

What is the difference between a biotic and abiotic factor?

Biotic factors are all living organisms in an ecosystem (plants, animals, microorganisms), while abiotic factors are non-living components (temperature, light, soil, water, atmosphere).

How does the nitrogen cycle work?

Nitrogen in the atmosphere is converted to usable forms by nitrogen-fixing bacteria in soil and legume plants. Plants use this nitrogen, animals eat plants, and decomposers return nitrogen to soil when organisms die.

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