NEET Biology Environmental Issues MCQs Set 14

Answer: (c) are sensitive to SO2

Explanation:
1. Lichens are very sensitive to sulphur dioxide and do not grow in polluted air, so they are indicators of SO2 pollution.

Teacher's Note:
1. Their absence shows polluted air.
2. Lichens are sensitive to SO2.

Answer: (a) excess NO2 and SO2 from burning fossil fuels

Explanation:
1. Acid rain forms when SO2 and NO2 released by burning fossil fuels dissolve in rain to form acids.

Teacher's Note:
1. pH of acid rain is below 5.6.
2. SO2 and NO2 make acid rain.

Answer: (c) increase in temperature due to increase in carbon dioxide concentration of atmosphere

Explanation:
1. The greenhouse effect is warming caused by gases such as CO2 trapping heat; rising CO2 raises temperature.

Teacher's Note:
1. Methane and CFCs also contribute.
2. CO2 increase warms the earth.

Answer: (a) methyl isocyanate

Explanation:
1. Methyl isocyanate (MIC) leaked at Bhopal in 1984.

Teacher's Note:
1. The plant made a pesticide.
2. MIC was the gas.

Answer: (b) biodegradable pollution

Explanation:
1. Domestic waste is mostly organic and decomposes by microbes, so it is biodegradable.

Teacher's Note:
1. Plastic is non-biodegradable.
2. Domestic waste is biodegradable.

Answer: (b) Carbon dioxide

Explanation:
1. Carbon dioxide is a normal component of air used in photosynthesis and is not usually called a pollutant, unlike the other three.

Teacher's Note:
1. In excess it is a greenhouse gas.
2. CO2 is not a normal pollutant.

Answer: (c) lead

Explanation:
1. Lead from leaded petrol is the most hazardous metal in vehicle exhaust, affecting the nervous system.

Teacher's Note:
1. Unleaded petrol reduced it.
2. Lead is the hazardous metal.

Answer: (a) O3

Explanation:
1. UV radiation splits oxygen in the stratosphere, and the atoms combine with O2 to form ozone.

Teacher's Note:
1. Ozone absorbs UV.
2. UV forms ozone.

Answer: (c) it is not easily/rapidly degraded in nature

Explanation:
1. DDT is not readily degraded, so it persists and accumulates in food chains.

Teacher's Note:
1. It becomes more concentrated in higher levels.
2. DDT persists in nature.

Answer: (b) sea gull/birds

Explanation:
1. DDT biomagnifies, so the top consumer, the fish-eating bird, has the highest deposition.

Teacher's Note:
1. Phytoplankton have the least.
2. Top level has most DDT.

Answer: (c) reduction in oxygen

Explanation:
1. Sewage is decomposed by microbes which use up dissolved oxygen, so fish die from oxygen shortage.

Teacher's Note:
1. BOD rises with sewage.
2. Oxygen falls and fish die.

Answer: (a) Minamata disease

Explanation:
1. Mercury poisoning from eating contaminated fish caused Minamata disease in Japan.

Teacher's Note:
1. Mercury affects the nervous system.
2. Mercury causes Minamata disease.

Answer: (b) above 80 dB

Explanation:
1. Noise above about 80 dB is hazardous and can damage hearing.

Teacher's Note:
1. Safe limit is lower.
2. Above 80 dB is hazardous.

Answer: (a) automobile exhausts

Explanation:
1. In big cities, vehicle exhausts are the main source of air pollution.

Teacher's Note:
1. They release CO, NOx and particles.
2. Vehicles pollute city air most.

Answer: (a) increase

Explanation:
1. Sewage supplies organic matter that microbes oxidise, so the biochemical oxygen demand increases.

Teacher's Note:
1. BOD measures organic load.
2. Sewage raises BOD.

Answer: (d) sulphur dioxide

Explanation:
1. Sulphur dioxide from industries and a refinery makes acid rain which corrodes the marble of the Taj Mahal.

Teacher's Note:
1. It is called marble cancer.
2. SO2 harms the Taj.

Answer: (d) it increases competition with fishes for dissolved oxygen

Explanation:
1. Microbes decomposing sewage compete with fish for dissolved oxygen, so fish die.

Teacher's Note:
1. CO2 is not the main reason.
2. Oxygen competition kills fish.

Answer: (d) Ukrain in 1986 and Bhopal in 1984

Explanation:
1. The Chernobyl nuclear accident happened in Ukraine in 1986 and the Bhopal MIC tragedy in 1984.

Teacher's Note:
1. Both were industrial disasters.
2. Chernobyl 1986, Bhopal 1984.

Answer: (a) Escherichia coli

Explanation:
1. Escherichia coli lives in the human intestine, so its presence in water indicates faecal contamination.

Teacher's Note:
1. Coliform tests use this.
2. E. coli indicates polluted water.

Answer: (d) sewage and agricultural fertilizers

Explanation:
1. Phosphate in water comes from sewage and detergents and from agricultural fertilizers, which leads to eutrophication.

Teacher's Note:
1. Run-off carries fertilizer.
2. Sewage and fertilizers add phosphate.

Answer: (b) Antarctica

Explanation:
1. The ozone hole is largest over Antarctica because of very cold stratospheric clouds.

Teacher's Note:
1. It appears in spring.
2. Hole is over Antarctica.

Answer: (d) depletion of ozone layer

Explanation:
1. Ozone depletion allows more UV to reach the earth, causing skin cancer and other skin disorders.

Teacher's Note:
1. UV also harms eyes.
2. Less ozone, more skin problems.

Answer: (d) Nitrous oxide

Explanation:
1. Nitrous oxide is released from agricultural fields by use of nitrogen fertilizers and is a greenhouse gas.

Teacher's Note:
1. Methane comes from paddy fields.
2. N2O comes from fields.

Answer: (d) O3 layer

Explanation:
1. Nitrogen oxides from supersonic jets in the stratosphere destroy ozone and thin the O3 layer.

Teacher's Note:
1. CFCs also deplete ozone.
2. Jets thin the ozone layer.

Answer: (c) El Nino

Explanation:
1. The periodic warm ocean current in the East Pacific off Peru is called El Nino.

Teacher's Note:
1. It changes weather widely.
2. Warm Peru surge is El Nino.

Answer: (c) it reacts with haemoglobin

Explanation:
1. Carbon monoxide binds to haemoglobin much more strongly than oxygen, so it reduces oxygen carrying and is a pollutant.

Teacher's Note:
1. It forms carboxyhaemoglobin.
2. CO combines with haemoglobin.