Our Environment — Karnataka (SSLC) Class 10 Science Solutions (Free)

Free step-by-step Karnataka (SSLC) Class 10 Science solutions for "Our Environment" — important questions with detailed answers, download PDF for board exam preparation.

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TL;DR: Free step-by-step Karnataka (SSLC) Class 10 Science solutions for "Our Environment" — important questions with detailed answers, download PDF for boar…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Sep 17, 2026

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Our Environment — Textbook Questions Answered (7)

Q1: Define an ecosystem. Explain food chains and food webs with an example.

Ecosystem: community of living organisms (biotic) and non-living environment (abiotic) interacting together. Food chain: linear transfer of energy (grass → grasshopper → frog → eagle). Food web: interconnected food chains showing multiple feeding relationships. Each organism depends on multiple food sources; removal of one affects entire web.

Q2: What is biomagnification? Explain how pesticides accumulate in organisms.

Biomagnification: increase in concentration of toxic substances (pesticides, heavy metals) as they move up the food chain. E.g., pesticide on grass (0.01 ppm) → grasshopper eats grass (0.1 ppm) → bird eats grasshoppers (1 ppm) → hawk eats birds (10 ppm). Top predators accumulate highest, causing death/deformities.

Q3: What is the ozone layer? How is it being depleted? What are the consequences?

Ozone layer (15–35 km altitude) absorbs UV-B radiation, protecting life from damage. Depletion caused by CFCs (chlorofluorocarbons) from refrigerators, aerosols breaking down ozone. Consequences: increased UV radiation → skin cancer, cataracts, immune suppression, phytoplankton damage, crop failure. Montreal Protocol (1987) banned CFCs.

Q4: Explain the greenhouse effect and its role in global warming.

Greenhouse effect: CO₂, CH₄, N₂O, water vapor trap infrared radiation, warming Earth. Necessary for life (keeps ~15°C livable), but excess gases from burning fossil fuels increase effect. Result: global temperature rise (now ~1.1°C above pre-industrial) → sea level rise, extreme weather, species extinction, agricultural losses.

Q5: What is acid rain? What causes it and what are its effects?

Acid rain: precipitation with pH < 5.6, caused by SO₂ and NO₂ from burning coal, petroleum combustion. SO₂ + H₂O → H₂SO₄; NO₂ + H₂O → HNO₃. Effects: (1) Corrodes buildings/statues (Taj Mahal), (2) Acidifies soil/lakes (kills aquatic life), (3) Damages forests, (4) Leaches toxic metals into groundwater.

Q6: What is meant by waste segregation? Explain the 3Rs principle.

Waste segregation: sorting waste into biodegradable (food, leaves) and non-biodegradable (plastic, glass, metal) at source. 3Rs: (1) Reduce—minimize waste generation, (2) Reuse—use items multiple times (bottles, bags), (3) Recycle—convert waste into new products (paper, plastic, metal). Reduces landfill burden and resource extraction.

Q7: What is eutrophication? How does it degrade aquatic ecosystems?

Eutrophication: excessive nutrient enrichment (N, P from fertilizers, sewage) causing algal bloom. Algae die and decompose; bacteria consume oxygen, creating dead zones. Oxygen depletion (hypoxia) kills fish and aquatic life. Prevents light penetration, kills submerged plants. Water becomes murky, foul-smelling. Lakes lose biodiversity.

NCERT Solutions: Our Environment — the CBSE version of this same topic.
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Metals and Non Metals — more Karnataka (SSLC) Class 10 Science.
Carbon and Its Compounds — more Karnataka (SSLC) Class 10 Science.
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