Our Environment — Class 10 Science MCQs

NCERT | CBSE Curriculum

Practice 100+ MCQs on Our Environment for Class 10.
Learn about Ecosystem, food chain, food web, ozone layer, greenhouse effect, biodegradable & biomagnification.
Instant answers & performance report.

Score:
0
Time:
05:00

Quick Revision: Our Environment

  • Ecosystem: Interaction of biotic (living) and abiotic (non-living) components in an area.
  • Biotic Components: Producers, consumers, decomposers.
  • Producers (Autotrophs): Green plants – convert solar energy to chemical energy via photosynthesis.
  • Consumers (Heterotrophs): Herbivores (primary), carnivores (secondary/tertiary), omnivores, parasites.
  • Decomposers: Bacteria/fungi – break down dead matter, recycle nutrients.
  • Food Chain: Linear sequence of who eats whom (e.g., Grass → Grasshopper → Frog).
  • Trophic Levels: Steps in a food chain (Producers → Primary → Secondary → Tertiary consumers).
  • 10% Law (Lindeman's Law): Only ~10% energy transferred to next trophic level; rest lost as heat/metabolism.
  • Food Web: Network of interconnected food chains; increases ecosystem stability.
  • Energy Flow: Unidirectional (Sun → Producers → Consumers → Decomposers).
  • Nutrient Cycling: Cyclic flow of nutrients (C, N, P) via biogeochemical cycles.
  • Biodegradable Waste: Can be decomposed by microbes (e.g., paper, vegetable peels).
  • Non-biodegradable Waste: Cannot be decomposed (e.g., plastic, metals, glass).
  • Biological Magnification: Increase in concentration of non-biodegradable chemicals at higher trophic levels (e.g., DDT in birds).
  • Ozone Layer (O₃): In stratosphere; absorbs harmful UV radiation.
  • Ozone Depletion: Caused by CFCs, halons; leads to ozone hole, increased UV exposure.
  • Effects of Ozone Depletion: Skin cancer, cataracts, reduced phytoplankton, crop damage.
  • Montreal Protocol (1987): International treaty to phase out ozone-depleting substances.
  • Waste Management: Reduce, Reuse, Recycle (3 R's); composting, safe disposal.
  • Ecosystem Types: Natural (forest, pond) and artificial (garden, aquarium).

External Resources: Byjus - Our Environment | Khan Academy - Ecology

Chapter Summary: Our Environment

Our Environment MCQ Class 10 connects you to the invisible web of life that sustains our planet. We learn how energy flows and nutrients cycle through ecosystems, why some wastes vanish while others pile up for centuries, and how human actions—from using pesticides to discarding plastics—ripple through food chains and even damage the protective ozone shield far above us.

We study ecosystems and their components, food chains and webs, and the 10% law of energy transfer. We understand the difference between biodegradable and non-biodegradable substances, the phenomenon of biological magnification, and the causes and effects of ozone layer depletion. We also learn about waste management and the 3 R's (Reduce, Reuse, Recycle).

This high-scoring chapter demands clarity on diagram-based questions, numerical problems on energy transfer, and conceptual explanations of environmental issues. Regular practice builds confidence in tackling both theoretical and application-based questions.