NEET Biology Environmental Issues MCQs Set 20

Answer: (d) Mercury

Explanation:
1. Hence option (d) is correct: Mercury

Teacher's Note:
1. Minamata disease was caused by mercury in industrial waste.
2. Mercury entered fish and then people.

Answer: (c) A non-biodegradable pollutant

Explanation:
1. D.D.T. is a non-biodegradable pollutant.
2. Hence option (c) is correct: A non-biodegradable pollutant

Teacher's Note:
1. DDT does not break down in nature, so it builds up in food chains.
2. It is a persistent pollutant.

Answer: (b) Depletion of ozone layer

Explanation:
1. Due to depletion of ozone layer.
2. Hence option (b) is correct: Depletion of ozone layer

Teacher's Note:
1. Ozone depletion lets more UV-B reach the earth.
2. This increases skin cancer and cataract.

Answer: (d) Antarctica

Explanation:
1. Hence option (d) is correct: Antarctica

Teacher's Note:
1. The ozone hole forms mainly over Antarctica because of very cold polar stratospheric clouds.
2. CFC chlorine destroys ozone there in spring.

Answer: (d) Less than the present

Explanation:
1. Less than present i.e. reduced to –18°C.
2. Hence option (d) is correct: Less than the present

Teacher's Note:
1. Without CO2 the greenhouse effect would be weaker and the earth about minus 18 degrees Celsius.
2. So the temperature would be lower than at present.

Answer: (d) Doha

Explanation:
1. The second commitment period for Kyoto Protocol was decided at Doha.
2. Hence option (d) is correct: Doha

Teacher's Note:
1. The second commitment period of the Kyoto Protocol was decided at Doha in 2012.
2. Durban and Bali were earlier meetings.

Answer: (a) Bhopal 1984, Ukrain 1986

Explanation:
1. Hence option (a) is correct: Bhopal 1984, Ukrain 1986

Teacher's Note:
1. The Bhopal gas leak was in 1984 and the Chernobyl accident in Ukraine in 1986.
2. Both were industrial disasters.

Answer: (a) Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.

Explanation:
1. Nitrate and phosphate in a water bodies result more fertile nature of water called eutrophication, that increases BOD and huge growth of algae called Algal Bloom.
2. Hence option (a) is correct: Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.

Teacher's Note:
1. Excess nitrates and phosphates enrich the water and cause eutrophication.
2. The nutrient enrichment makes algae multiply into blooms.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. Biomagnification of DDT can reduce bird population because it causes thinning of egg shell.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. Biomagnified DDT thins the egg shells of birds.
2. The Reason says thickening, so it is false.

Answer: (a) Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.

Explanation:
1. Ecological sanitation is sustainable system for handling human excreta. It is a practical and hygenic method of using dry composting toilets.
2. Hence option (a) is correct: Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.

Teacher's Note:
1. Ecological sanitation uses dry composting toilets to handle human excreta sustainably.
2. The Reason describes how it works.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. El-Nino is climatic change which causes deleterious environmental changes. Increased smog trophospheric ozone is due to photochemical.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. El Nino brings harmful climate changes.
2. The Reason about tropospheric ozone is not the correct cause.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. An electrostatic precipitator removes more than 99 percent of particulate matter.
2. The corona wires give the particles a negative charge, and the Reason misstates this, so it is false.
3. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. An ESP removes over 99 percent of particles.
2. Its wires give particles a negative charge, so the Reason about the anode is wrong.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. Montreal Protocol suggested the reduction of ozone depleting substances (ODS). A landmark international agreement taken in Montreal - Canada in 1987.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. The Montreal Protocol (1987) reduces ODS.
2. The Rio Earth Summit is another event, so the Reason is wrong.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. Intensive agriculture leads to negative soil pollution because It decreases useful mineral contents.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. Intensive farming removes minerals from the soil, a form of negative pollution.
2. The Reason is wrong because it decreases useful minerals.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. PAN is produced by photochemical reaction.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. PAN is a secondary pollutant formed in sunlight.
2. The Reason is false because light is needed.

Answer: (c) Assertion is true but the Reason is false.

Explanation:
1. The toxic substance cannot be metabolised or excreted by organism.
2. Hence option (c) is correct: Assertion is true but the Reason is false.

Teacher's Note:
1. Toxic substances that cannot be metabolised or excreted are biomagnified.
2. The Reason says the opposite, so it is false.

Answer: (b) Both Assertion and Reason are true but the Reason is not a correct explanation of the Assertion.

Explanation:
1. Polyblend was mixed with bitumen to lay roads.   
2. Hence option (b) is correct: Both Assertion and Reason are true but the Reason is not a correct explanation of the Assertion.

Teacher's Note:
1. Polyblend is a fine powder of recycled plastics, mixed with bitumen to lay roads.
2. The longer road life is true but does not explain what polyblend is.

Answer: (a) Hydrogen

Explanation:
1. Hydrogen burns to give water only, so it does not cause air pollution.
2. SO2, CO2 and CO all pollute or harm the atmosphere.
3. Hence option (a) is correct: Hydrogen

Teacher's Note:
1. Hydrogen is a clean fuel.
2. CO2 contributes to global warming.

Answer: (d) CO

Explanation:
1. Carbon monoxide from incomplete burning of fuel is the most harmful pollutant from vehicles.
2. It binds haemoglobin and reduces oxygen supply.
3. Hence option (d) is correct: CO

Teacher's Note:
1. CO is colourless and odourless.
2. It is dangerous in closed garages.

Answer: (b) Micro organism

Explanation:
1. Microorganisms break down the organic matter in sewage.
2. Penicillin is an antibiotic and does not purify sewage.
3. Hence option (b) is correct: Micro organism

Teacher's Note:
1. Sewage treatment depends on microbes.
2. Aerobic and anaerobic bacteria are used.

Answer: (b) Air pollutants released from oilrefinery of Mathura

Explanation:
1. Sulphur dioxide and other pollutants from the Mathura refinery form acids that corrode the marble of the Taj Mahal.
2. Floods and temperature are not the main cause.
3. Hence option (b) is correct: Air pollutants released from oilrefinery of Mathura

Teacher's Note:
1. SO2 forms acid rain.
2. Calcium carbonate of marble turns into calcium sulphate.

Answer: (c) 1972

Explanation:
1. The Wildlife (Protection) Act was enacted in India in 1972.
2. It protects endangered species and sets up sanctuaries and national parks.
3. Hence option (c) is correct: 1972

Teacher's Note:
1. 1972 is the year of the Wildlife Act.
2. Project Tiger started in 1973.