Natural Resources Test - 12

Running water carries soil sediments along with it as it flows. During floods, river water carries away the valuable top soil. This process is called soil erosion.

The correct answer is C.

Why alternatives A and B are wrong:

Solar radiations and soil organisms do not cause soil erosion.

Why alternative D is wrong:

Plant roots hold the soil together and prevent erosion. They do not cause erosion.

Earthquakes do not depend upon atmospheric conditions. They are governed by the processes taking place below the surface of Earth.

The correct answer is A.

Why alternative B is wrong:

The intensity of hurricanes increases because of excessive heat in the atmosphere.

Why alternative C is wrong:

The increase in atmospheric temperature leads to the melting of polar ice. This in turn results in the decrease in the extent of polar ice.

Why alternative D is wrong:

The increase in atmospheric temperature leads to the melting of glaciers. This in turn causes a rise in the global sea level.

Sand gets heated faster than water and water gets heated faster than air. Thus, sand will have the maximum temperature followed by water and air.

The correct answer is C.

Air is a bad conductor of heat. It does not become hot or cold very quickly. Thus, the presence of atmosphere around the Earth prevents a sudden decrease or increase in temperature of the Earth.

The correct answer is A.

Why alternative B is wrong:

Air is not a good conductor of heat.

Why alternatives C, D are wrong:

The temperature of air depends on the atmosphere.

Winds that blow from the sea toward the land will bring maximum rain because the moisture and vapour from the surface of the sea are carried to the land. The sea water is heated by sunlight causing evaporation. The water vapour condenses to form clouds and through precipitation falls in the form of rain.

The correct answer is B.

Why alternative A is wrong:

Winds blowing from sea to sea do not bring rainfall over land. Rainfall occurs on land when the winds from the sea or any other water bodies move over the land surface.

Why alternative C is wrong:

Winds blowing from the forest land to the sea do not cause rain over land.

Why alternative D is wrong:

Winds blowing from land to land do not contain any moisture. Therefore, these winds do not bring rain.

Precipitation in the form of rain occurs as a part of the water cycle. It does not influence wind formation.

The correct answer is C.

Why alternatives A, B and D are wrong:

Rotation of the Earth, differential heating of air and solar radiations heating the Earth are the various factors that influence the formation of winds.

Oxygen is inhaled from the atmosphere by humans. Water is not required for the uptake of oxygen.

The correct answer is B.

The temperature variations in air influence air pressure. Air has low pressure in hot regions and high pressure in cold regions. Air moves from a region of higher concentration to a region of lower concentration or from a region of high pressure to a region of low pressure.

The correct answer is B.

Wind and water both collide against the rocks bringing about weathering. Winds blow over the rocks when it moves from one region to another. Water too hits the rocks as it flows and causes it to break down into smaller pieces, thereby resulting in the weathering of rocks.

The correct answer is C.

Why alternative A is wrong:

Plants grow inside cracks and crevices in the rocks and cause them to expand. This process is called biological weathering. Plants do not bring about weathering in rocks by a process of constant collision.

Why alternative B is wrong:

The heat from the Sun causes the rocks to expand. The weathering that takes place as a result of this expansion and contraction is not brought about by the process of collision. Organisms do not influence the process of weathering.

Why alternative D is wrong:

Plants grow in the cracks in rocks cause the rocks to expand. This process is called biological weathering. The sun increases the temperature and thus expands the rocks. These processes do not describe weathering brought about by collision.

Expansion occurs when there is an increase in temperature. The Sun’s heat causes the rocks to expand. These rocks contract when there is a decrease in temperature. Thus, the Sun influences the process of weathering in rocks.

In the similar way, Water also plays an important role in the contraction and expansion of rocks. It enters rocks through the cracks on them. It freezes at low temperatures, thereby expanding the rocks. The rocks contract when the frozen water melts. This repeated expansion and contraction of rocks over time leads to their breaking down into smaller pieces called weathering.

The correct answer is D.

Why alternatives A, B and C are wrong:

Wind and organisms do cause weathering but these factors do not bring about the expansion and contraction in rocks.