Environment & Ecology: Protecting Our Planet: questions and answers
Study every question with its correct answer and explanation.
1. Which international treaty, agreed in 1987, set out to phase out ozone-depleting substances such as CFCs?
- A. Kyoto Protocol
- B. Montreal Protocol
- C. Paris Agreement
- D. Ramsar Convention
Answer: Montreal Protocol
The Montreal Protocol was signed on 16 September 1987, and that date is now marked as the International Day for the Preservation of the Ozone Layer. The ozone layer in the stratosphere absorbs most of the Sun's harmful ultraviolet (UV-B) radiation.
2. The Kyoto Protocol, adopted in 1997, set binding targets for developed countries to cut what?
- A. Greenhouse gas emissions
- B. Plastic waste in the oceans
- C. Trade in endangered species
- D. Use of chemical pesticides
Answer: Greenhouse gas emissions
Adopted in Japan in 1997 under the UN Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol required industrialised countries to reduce their greenhouse gas emissions. It was followed in 2015 by the Paris Agreement, which aims to keep global warming well below 2 °C above pre-industrial levels.
3. The Ramsar Convention of 1971 is an international treaty for the conservation of which type of ecosystem?
- A. Deserts
- B. Coral reefs
- C. Mountains
- D. Wetlands
Answer: Wetlands
The treaty is named after Ramsar, the Iranian city where it was signed on 2 February 1971 — a date now celebrated as World Wetlands Day. Parts of the Sundarbans mangrove forest, shared by Bangladesh and India, are listed as Ramsar sites.
4. In a food chain, what are green plants called?
- A. Primary consumers
- B. Decomposers
- C. Producers
- D. Secondary consumers
Answer: Producers
Green plants are producers because they make their own food from sunlight through photosynthesis, supplying energy to the rest of the food chain. Herbivores that eat plants are primary consumers, while bacteria and fungi act as decomposers, returning nutrients to the soil.
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5. According to the ecological '10 per cent law', roughly how much energy passes from one trophic level to the next?
- A. 1%
- B. 10%
- C. 50%
- D. 90%
Answer: 10%
On average only about 10% of the energy at one level of a food chain reaches the next; the rest is mostly used for life processes or lost as heat. This is why food chains rarely have more than four or five levels, and why a forest has far fewer tigers than deer.
6. Which pair of pollutants is mainly responsible for acid rain?
- A. Oxygen and nitrogen
- B. Methane and helium
- C. Ozone and argon
- D. Sulphur dioxide and nitrogen oxides
Answer: Sulphur dioxide and nitrogen oxides
Sulphur dioxide and nitrogen oxides, released mainly by burning coal and oil, react with water in the air to form sulphuric and nitric acids. Acid rain damages forests, lakes and buildings — its effect on the marble of the Taj Mahal is sometimes called 'marble cancer'.
7. Which greenhouse gas is released in large amounts by flooded rice paddies and by cattle during digestion?
- A. Methane
- B. Nitrogen
- C. Ozone
- D. Hydrogen
Answer: Methane
Microbes that live without oxygen — in waterlogged paddy fields and in the stomachs of cattle — produce methane (CH₄). Molecule for molecule, methane traps far more heat than carbon dioxide over a 20-year period, although it breaks down in the atmosphere much sooner.
8. What is the term for the build-up of a toxic substance such as DDT to higher and higher concentrations at each level of a food chain?
- A. Eutrophication
- B. Photosynthesis
- C. Biomagnification
- D. Ecological succession
Answer: Biomagnification
Pesticides like DDT are not easily broken down or excreted, so they collect in body fat and become more concentrated in each predator further up the chain. In the 20th century, DDT biomagnification caused dangerously thin eggshells in birds of prey such as eagles and falcons.
9. When fertiliser runoff overloads a lake or pond with nutrients, causing algal blooms and oxygen-starved water, what is the process called?
- A. Eutrophication
- B. Desertification
- C. Nitrogen fixation
- D. Deforestation
Answer: Eutrophication
Excess nitrates and phosphates make algae grow explosively; when the algae die, the bacteria decomposing them use up the dissolved oxygen, so fish and other animals can suffocate. Oxygen-depleted areas like this in the sea are often called 'dead zones'.
10. On which date is World Environment Day observed every year?
- A. 22 April
- B. 5 June
- C. 16 September
- D. 22 March
Answer: 5 June
World Environment Day, led by the UN Environment Programme (UNEP), is held on 5 June — the opening day of the 1972 Stockholm Conference on the Human Environment. Don't confuse it with Earth Day on 22 April or World Water Day on 22 March.