'Our Home: Earth, A Unique Life Sustaining Planet' — Practice

Question 1

What are the four main layers of Earth?

Accepted Answer

✦ Answer: From surface to centre: CRUST (rocky outer), MANTLE (mostly solid but flowing), OUTER CORE (liquid metal), INNER CORE (solid metal).

Question 2

Name the layer where the ozone is found.

Accepted Answer

✦ Answer: STRATOSPHERE (12-50 km up). The ozone layer blocks harmful UV-B radiation from Sun.

Question 3

Explain three major effects of climate change on India.

Accepted Answer

Step 1 — Glacier melting in Himalayas.
  Higher temperatures cause Himalayan glaciers to retreat faster. This threatens:
  • Indus, Ganga, Brahmaputra rivers (fed by glaciers)
  • Water supply for billions in India, Pakistan, Bangladesh
  • Long-term: glacier loss means river drying

Step 2 — Monsoon disruption.
  Climate change is making monsoon erratic:
  • Heavier downpours interrupted by dry spells
  • Late or early arrival
  • Spatial variability (some areas flood, others drought)
  • Agriculture (which depends on monsoon) is destabilised

Step 3 — More extreme weather.
  Increased frequency and intensity of:
  • Heatwaves: 45°C+ summers in North India
  • Cyclones: Arabian Sea cyclones (rare before) increasing
  • Floods: Mumbai, Chennai, Bengaluru repeatedly flooded
  • Droughts: longer dry periods in parts of India

Step 4 — Other effects.
  • Sea level rise threatens coastal cities (Mumbai, Chennai)
  • Species extinction
  • Health impacts (heat stroke, mosquito-borne disease spread)
  • Agricultural disruption

Step 5 — India's response.
  • Target 500 GW renewable energy by 2030
  • Net-zero by 2070 (COP26 pledge)
  • Massive solar parks (Bhadla, Pavagada)
  • Push for EVs
  • Mission LiFE (Lifestyle for Environment)

✦ Answer: Three major effects: (1) HIMALAYAN GLACIER MELTING (threatens river systems), (2) MONSOON DISRUPTION (erratic, threatens agriculture), (3) EXTREME WEATHER (heatwaves, cyclones, floods). India is among the most vulnerable nations and is taking action through renewable energy push and net-zero target by 2070.

Question 4

Discuss India's approach to environmental conservation and what students can contribute.

Accepted Answer

Step 1 — India's environmental context.
  India has 17% of world's population, 4% of freshwater, 2.4% of land area. We face significant pressure on natural resources. At the same time, India has rich biodiversity, ancient sustainable traditions, and is moving rapidly to address modern challenges.

Step 2 — Government initiatives.
  • CLEAN ENERGY: target 500 GW renewable by 2030; world's largest solar parks (Bhadla, Pavagada)
  • NET-ZERO: India's COP26 pledge for net-zero by 2070
  • CLEAN GANGA MISSION: river restoration
  • SWACHH BHARAT: sanitation and cleanliness drive
  • NATIONAL CLEAN AIR PROGRAMME: reduce PM 2.5 by 40% in 122 cities
  • PROJECT TIGER, ELEPHANT: wildlife protection
  • NATIONAL POLICIES on water, forests, biodiversity

Step 3 — Policy successes.
  • Tiger population: 1,400 (2008) → 3,167 (2022)
  • Forest cover: increased to 24.62% of land
  • Renewable energy: 200 GW achieved (target 500 GW)
  • Bharat Stage VI vehicle norms (matches Euro 6)
  • Plastic ban in several states

Step 4 — Ongoing challenges.
  • Air pollution: many of world's most polluted cities are Indian
  • Water scarcity: groundwater depletion alarming
  • Plastic waste: massive issue
  • Deforestation continues in some areas
  • Climate change impacts mounting

Step 5 — What students can do.
  PERSONAL ACTIONS:
  • Use cycle/walk for short trips
  • Save electricity (turn off lights, fans)
  • Save water (no wastage, fix leaks)
  • Use cloth bags, refuse single-use plastic
  • Plant trees on birthdays
  • Compost kitchen waste
  • Repair instead of replace

Step 6 — Community actions.
  • Form environment clubs at school
  • Organise clean-up drives in neighbourhood
  • Visit and learn from national parks
  • Educate parents, siblings, friends
  • Plant and maintain a kitchen garden
  • Support local farmers (less transport carbon)

Step 7 — Citizen science.
  • Use apps like iNaturalist, eBird to record species
  • Air quality apps to track pollution
  • Climate citizen monitoring

Step 8 — Future as professional.
  Future careers in:
  • Renewable energy engineering
  • Conservation biology
  • Environmental policy
  • Sustainable agriculture
  • Green building design
  • Climate science

Step 9 — Influence others.
  • Share knowledge
  • Vote for environmentally conscious leaders (when older)
  • Choose sustainable brands
  • Speak up against environmental harm

Step 10 — Long-term outlook.
  India's environment will largely depend on YOUR generation's actions. Started today, sustainable habits multiply over decades. India can become both prosperous and ecologically vibrant — but requires every citizen's contribution.

Step 11 — Indian heritage as guide.
  Ancient India revered nature: trees (peepal), animals (cow), rivers (Ganga). Modern science confirms this wisdom. Sustainable living is in our DNA — we need only revive it.

✦ Answer: India is taking major steps: 500 GW renewable target, net-zero by 2070, Clean Ganga, Swachh Bharat, Project Tiger. Successes include doubled tiger population, growing forest cover, expanding renewables. STUDENTS can contribute through: personal habits (save water/electricity, reduce plastic, plant trees), community actions (clean-up drives, school environment clubs), citizen science (recording species), educating others, and choosing future careers in environmental fields. Every individual matters when multiplied by 1.4 billion.

Practice — 'Our Home: Earth, A Unique Life Sustaining Planet'

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