Environmental Science— Concepts, Formulas & Shortcuts
- The ozone layer lies in the stratosphere and absorbs harmful ultraviolet radiation.
- Chlorofluorocarbons (CFCs) deplete ozone; the Montreal Protocol phased them out.
- Principal greenhouse gases: carbon dioxide, methane, nitrous oxide and water vapour.
- World Environment Day is 5 June; Earth Day is 22 April.
- Biodegradable waste decomposes naturally; plastics and metals do not.
- Project Tiger was launched in 1973 to conserve the Bengal tiger.
Environmental Science Practice Questions with Answers
Attempt each question first, then open the explanation. All 10 questions below are free to read and require no signup.
Q1.The ozone layer is found in which atmospheric layer?
Moderate- ATroposphere
- BStratosphere
- CMesosphere
- DThermosphere
Environmental Science question 1 of 10+Show Answer & Explanation
Answer: B. Stratosphere
Explanation: The ozone layer lies in the stratosphere and shields the earth from ultraviolet radiation.
Q2.Which substances are chiefly responsible for ozone depletion?
Moderate- ACarbon dioxide
- BChlorofluorocarbons
- CMethane
- DNitrogen
Environmental Science question 2 of 10+Show Answer & Explanation
Answer: B. Chlorofluorocarbons
Explanation: CFCs release chlorine atoms that catalytically destroy ozone.
Q3.World Environment Day is observed on:
Easy- A22 April
- B5 June
- C16 September
- D1 December
Environmental Science question 3 of 10+Show Answer & Explanation
Answer: B. 5 June
Explanation: World Environment Day falls on 5 June each year.
Q4.Which of these is a non-biodegradable waste?
Easy- AVegetable peel
- BPaper
- CPlastic bottle
- DCow dung
Environmental Science question 4 of 10+Show Answer & Explanation
Answer: C. Plastic bottle
Explanation: Plastic resists microbial decomposition and persists for centuries.
Q5.Project Tiger was launched in India in:
Moderate- A1963
- B1973
- C1983
- D1993
Environmental Science question 5 of 10+Show Answer & Explanation
Answer: B. 1973
Explanation: Project Tiger began in 1973 to protect the dwindling tiger population.
Q6.Which gas is the principal contributor to global warming?
Easy- AOxygen
- BCarbon dioxide
- CNitrogen
- DArgon
Environmental Science question 6 of 10+Show Answer & Explanation
Answer: B. Carbon dioxide
Explanation: Carbon dioxide is the most significant long-lived greenhouse gas.
Q7.Acid rain is caused mainly by emissions of:
Moderate- ACarbon dioxide and oxygen
- BSulphur dioxide and nitrogen oxides
- CMethane and ozone
- DHelium and argon
Environmental Science question 7 of 10+Show Answer & Explanation
Answer: B. Sulphur dioxide and nitrogen oxides
Explanation: SO₂ and NOₓ dissolve in atmospheric moisture to form sulphuric and nitric acids.
Q8.Earth Day is observed on:
Moderate- A22 April
- B5 June
- C21 March
- D8 August
Environmental Science question 8 of 10+Show Answer & Explanation
Answer: A. 22 April
Explanation: Earth Day is marked worldwide on 22 April.
Q9.A biosphere reserve is designated primarily to:
Easy- AExtract minerals
- BConserve biodiversity and ecosystems
- CBuild industry
- DPromote farming
Environmental Science question 9 of 10+Show Answer & Explanation
Answer: B. Conserve biodiversity and ecosystems
Explanation: Biosphere reserves protect representative ecosystems along with their genetic diversity.
Q10.The Montreal Protocol deals with:
Difficult- AGreenhouse gases
- BOzone-depleting substances
- CMarine pollution
- DNuclear testing
Environmental Science question 10 of 10+Show Answer & Explanation
Answer: B. Ozone-depleting substances
Explanation: It is the international treaty that phased out CFCs and other ozone-depleting chemicals.
Environmental Science — Frequently Asked Questions
What causes depletion of the ozone layer?+
Chlorofluorocarbons and related halogenated compounds. Released from refrigerants and aerosols, they break down ozone molecules in the stratosphere — which is why the Montreal Protocol phased them out.
What is the difference between biodegradable and non-biodegradable waste?+
Biodegradable waste, such as food and paper, is broken down by micro-organisms. Non-biodegradable waste like plastic, glass and metal persists in the environment for decades or centuries.
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