Natural Resources Test - 13

The depletion of ozone layer is caused by CFCs, that is, chlorofluorocarbons. The combustion of fossil fuels does not release CFCs. Hence, the use of fossil fuels does not lead to the depletion of ozone layer.

The correct answer is D.

Why alternative A is wrong:

The combustion of fossil fuels releases a lot of carbon dioxide. Carbon dioxide is a greenhouse gas and traps the heat from sunlight. This causes Earth’s temperature to increase. This is known as the greenhouse effect.

Why alternative B is wrong:

The combustion of coal releases a lot of sulphur dioxide into the atmosphere. This sulphur dioxide changes into sulphuric acid in the atmosphere and causes acid rains. Acid rains decrease soil fertility.

Why alternative C is wrong:

The combustion of fossil fuels releases a lot of harmful gases and smoke which cause air pollution. Hence, the burning of fossil fuels increases the amount of pollutants in the atmosphere.

Eutrophication is caused by water pollution. When polluted water from farms, rich in fertilizers (mostly nitrogen and phosphorous), mixes with water in lakes and rivers, it triggers the growth of aquatic vegetation, which then consumes all the oxygen present in water. This leads to the death of aquatic life.

The correct answer is D.

Why alternatives A, B and C are wrong:

Eutrophication is caused by an increase in the nutrient content of a water body, especially nitrogen and phosphorous. Thus, eutrophication is caused by water pollution, and not by air, land, or noise pollution. Hence, alternatives A, B, and C are incorrect.

Forests are of immense importance to the biome of a region. They clean air by absorbing harmful carbon dioxide gas. The destruction of the ozone layer is caused by chlorofluorocarbons or aerosols. Deforestation does not lead to the destruction of the ozone layer.

The correct answer is D.

Why alternatives A, B and C are wrong:

Deforestation leads to a reduction in the number of trees. As a result, the concentration of harmful carbon dioxide gas increases in atmosphere. This leads to global warming, greenhouse effect, and pollution of environment. Hence, alternatives A, B, and C are incorrect.

Consumption of water that contains pesticides like DDT may lead to endocrine and reproductive damage problems.

The correct answer is A.

Why alternatives B, C and D are wrong:

Consumption of water contaminated by pesticides generally does not affect respiratory, cardiac, and nervous systems. Hence, alternatives B, C, and D are incorrect.

The burning or burying of plastic materials after use will not help in the conservation of natural resources. The burning of plastic releases harmful gases and causes air pollution. When plastic is buried, it remains there for a very long time. This is because plastics are non-biodegradable substances. Plastics can be recycled and should never be disposed in the environment directly.

The correct answer is C.

Why alternative A is wrong:

Traveling by a bicycle helps in the conservation of petroleum and diesel. It also decreases air pollution.

Why alternative B is wrong:

Switching off lights when not needed helps in saving electricity.

Why alternative D is wrong:

Water is very important for the sustenance of life. Fresh water reserves are limited on Earth. Therefore, the careful use of water helps in its conservation.

Nitric oxide does not lead to the greenhouse effect since it does not trap the sun’s radiation in the atmosphere.

The correct answer is C.

Why alternative A, B and D are wrong:

Alternatives A, B and D are incorrect since they are all greenhouse gases.

The use of public transport for traveling helps in the conservation of fuel. This lowers the number of vehicles on road, thereby reducing air pollution as well.

The correct answer is C.

Why alternative A is wrong:

Keeping the television switched on causes wastage of electricity. A television or any other electrical device should be turned off after their use. This helps in saving electricity.

Why alternative B is wrong:

Taking more food than one can eat causes wastage of food.

Why alternative D is wrong:

Keeping the tap open while brushing teeth causes wastage of water. The tap should be closed when water is not needed. The continuous flow of water results in its wastage.

Sun is the main source of heat and light energy on Earth. Sunlight is absorbed by the plants and is used for photosynthesis. Sunlight is essential for the plants to make food.

The correct answer is D.

Why alternative A is wrong:

Clouds are tiny droplets of water particles suspended in the atmosphere. They do not emit light.

Why alternative B is wrong:

Moon does not emit light. It reflects sunlight.

Why alternative C is wrong:

Only a small amount of light comes from the stars to Earth’s surface. Plants cannot use the light coming from the stars for photosynthesis.

Heating effect is caused by infra-red (IR) rays. Greenhouse gases present in Earth’s atmosphere absorb this radiation and trap its heat to maintain the temperature of Earth’s atmosphere. Hence, greenhouse effect is the result of the trapping of infra-red rays.

The correct answer is B.

Why alternative A is wrong:

Ultra-violet rays are high energy radiations emitted by Sun. These rays severely harm living tissues. The ozone layer present in the stratosphere absorbs most of the ultra-violet radiation that is incident on Earth’s atmosphere.

Why alternative C is wrong:

Gamma rays emitted by Sun are absorbed by oxygen and nitrogen present in atmosphere, but oxygen and nitrogen. Greenhouse gases do not absorb or trap gamma radiation. Hence, this alternative is incorrect.

Why alternative D is wrong:

Visible rays or light is that component of solar radiation which helps one to see. Visible light consists of seven different colors of the rainbow. Greenhouse gases do not absorb or trap visible radiation. Hence, this alternative is incorrect.