1
The ozone layer is found in which layer of the atmosphere?
Correct answer: C. Stratosphere
Most atmospheric ozone lies in the stratosphere, about 15–35 km above the surface, where it absorbs harmful ultraviolet rays.
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Environment and Ecology MCQs
Solved Everyday Science MCQs on the environment: ozone layer, climate agreements, pollution, acid rain, ecosystems, biodiversity and conservation.
25 MCQsUpdated 27 October 2026
This set covers environmental science and the agreements that protect the planet: the ozone layer, greenhouse gases and climate treaties such as the Kyoto Protocol, the Ramsar Convention on wetlands, renewable energy and pollution.
Environmental questions often combine science with dates and international agreements. Note what each convention or protocol protects, since options frequently swap them.
- 2
Which chemicals are mainly responsible for depleting the ozone layer?
Correct answer: A. Chlorofluorocarbons (CFCs)
CFCs, once used in fridges, air conditioners and aerosol sprays, release chlorine that destroys ozone molecules.
easy - 3
The international treaty to phase out ozone-depleting substances is the:
Correct answer: D. Montreal Protocol
The Montreal Protocol (1987) is regarded as one of the most successful environmental agreements. The ozone layer is slowly recovering.
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The Kyoto Protocol, adopted in 1997, deals with:
Correct answer: A. Reducing greenhouse gas emissions
The Kyoto Protocol set binding emission-reduction targets for industrialized countries.
medium - 5
The Paris Agreement on climate change was adopted in:
Correct answer: C. 2015
Adopted at COP21 in December 2015, it aims to keep global warming well below 2 °C, and preferably at 1.5 °C, above pre-industrial levels.
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Acid rain is mainly caused by emissions of:
Correct answer: B. Sulphur dioxide and nitrogen oxides
SO₂ and NOₓ from burning fossil fuels react with water in the air to form sulphuric and nitric acids.
medium - 7
World Environment Day is celebrated every year on:
Correct answer: D. 5 June
The UN has celebrated World Environment Day on 5 June since 1974. Earth Day is on 22 April.
easy - 8
Earth Day is observed every year on:
Correct answer: D. 22 April
Earth Day began in 1970 and is now marked worldwide on 22 April. World Water Day is on 22 March.
easy - 9
The UN Environment Programme (UNEP) is headquartered in:
Correct answer: B. Nairobi
UNEP, founded in 1972, is based in Nairobi, Kenya, making it one of the few UN agencies headquartered in Africa.
medium - 10
The Ramsar Convention (1971) is concerned with the conservation of:
Correct answer: A. Wetlands
The convention, signed in Ramsar, Iran, protects wetlands of international importance. Pakistan has many Ramsar sites, including Haleji Lake.
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In a food chain, green plants are known as:
Correct answer: A. Producers
Plants make their own food by photosynthesis, so they are producers. Animals are consumers, and bacteria and fungi are decomposers.
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Organisms that break down dead plants and animals are called:
Correct answer: B. Decomposers
Decomposers such as bacteria and fungi recycle nutrients back into the soil.
easy - 13
Which of the following is a renewable source of energy?
Correct answer: A. Solar energy
Solar energy is naturally replenished. Coal, gas and oil are fossil fuels that take millions of years to form.
easy - 14
Which of these materials is biodegradable?
Correct answer: C. Paper
Paper is broken down by microorganisms in a relatively short time. Plastic can persist for hundreds of years.
easy - 15
The "3 Rs" of waste management stand for:
Correct answer: B. Reduce, Reuse, Recycle
Reducing waste comes first, then reusing items, and finally recycling materials into new products.
easy - 16
The Indus River Dolphin, an endangered species found in Pakistan, is famous for being:
Correct answer: D. Almost blind
The Indus river dolphin has very poor eyesight and relies on echolocation to navigate the muddy Indus.
medium - 17
Which organization publishes the "Red List" of threatened species?
Correct answer: A. IUCN
The International Union for Conservation of Nature (IUCN) Red List assesses the extinction risk of species worldwide.
medium - 18
The process by which fertile land turns into desert is called:
Correct answer: C. Desertification
Desertification is caused by drought, overgrazing, deforestation and poor farming practices.
easy - 19
The large-scale cutting down of forests is called:
Correct answer: D. Deforestation
Deforestation removes forests. Afforestation creates new forests, and reforestation replants areas that were cut.
easy - 20
Smog that covers cities like Lahore in winter is mainly a combination of:
Correct answer: C. Smoke and fog
The word "smog" combines smoke and fog. Vehicle exhaust, industry and crop burning add pollutants that are trapped near the ground in cold, still weather.
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