The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Gneissic rocks are usually medium- to coarse-foliated and largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Mica minerals make some rocks sparkle! They are often found in igneous rocks such as granite and metamorphic rocks such as schist. Most schists are mica schists, but graphite and chlorite schists are also common. Schist is a crystalline metamorphic rock, mostly composed of more than 50% tabular and elongated minerals.

Correct Option: B

The schists constitute a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Gneissic rocks are usually medium- to coarse-foliated and largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Mica minerals make some rocks sparkle! They are often found in igneous rocks such as granite and metamorphic rocks such as schist. Most schists are mica schists, but graphite and chlorite schists are also common. Schist is a crystalline metamorphic rock, mostly composed of more than 50% tabular and elongated minerals.

Loess is an Aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20– 50 micrometer size range, twenty percent or less clay and the balance equal parts sand and silt that are loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs. The word loess, with connotations of origin by winddeposited accumulation, is of German origin and means “loose.” It was first applied to Rhine River valley loess about 1821.

Correct Option: A

Loess is an Aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20– 50 micrometer size range, twenty percent or less clay and the balance equal parts sand and silt that are loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs. The word loess, with connotations of origin by winddeposited accumulation, is of German origin and means “loose.” It was first applied to Rhine River valley loess about 1821.

Highly viscous lava tends to entrap gas, which form vesicles (bubbles) within the rock as they rise to the surface. Lava with low viscosity tends to easily release bubbling gases as they are formed. Lavas also may contain many other components, sometimes including solid crystals of various minerals, fragments of exotic rocks known as xenoliths and fragments of previously solidified lava. Volcanic eruptions are caused by magma (a mixture of liquid rock, crystals, and dissolved gas) expelled onto the Earth’s surface. At depth in the Earth nearly all magmas contain gas dissolved in the liquid, but the gas forms a separate vapor phase when pressure is decreased as magma rises toward the surface of the Earth. This is similar to carbonated beverages which are bottled at high pressure. The high pressure keeps the gas in solution in the liquid. Gas gives magmas their explosive character, because volume of gas expands as pressure is reduced.

Correct Option: A

Highly viscous lava tends to entrap gas, which form vesicles (bubbles) within the rock as they rise to the surface. Lava with low viscosity tends to easily release bubbling gases as they are formed. Lavas also may contain many other components, sometimes including solid crystals of various minerals, fragments of exotic rocks known as xenoliths and fragments of previously solidified lava. Volcanic eruptions are caused by magma (a mixture of liquid rock, crystals, and dissolved gas) expelled onto the Earth’s surface. At depth in the Earth nearly all magmas contain gas dissolved in the liquid, but the gas forms a separate vapor phase when pressure is decreased as magma rises toward the surface of the Earth. This is similar to carbonated beverages which are bottled at high pressure. The high pressure keeps the gas in solution in the liquid. Gas gives magmas their explosive character, because volume of gas expands as pressure is reduced.

The prospect of producing electricity from the hydrological resources of the Plateau region lies not, as has been suggested, in the ‘region’s fast flowing rivers’. The flow rate of most rivers in the region is relatively slow. However, the sloped topography of the plateau itself provides enormous capacity to generate electricity. All existing and planned hydropower projects in the region are based on the simple engineering principle of utilizing gravity to generate energy from the region’s rivers. The steep escarpments found in the south-eastern portion of the region provide the natural topographical mechanism to subject the region’s water resources to the energy-producing force of gravity.

Correct Option: D

The prospect of producing electricity from the hydrological resources of the Plateau region lies not, as has been suggested, in the ‘region’s fast flowing rivers’. The flow rate of most rivers in the region is relatively slow. However, the sloped topography of the plateau itself provides enormous capacity to generate electricity. All existing and planned hydropower projects in the region are based on the simple engineering principle of utilizing gravity to generate energy from the region’s rivers. The steep escarpments found in the south-eastern portion of the region provide the natural topographical mechanism to subject the region’s water resources to the energy-producing force of gravity.

Tropical grasslands (Savannas) are located near the equator, between the Tropic of Cancer and the Tropic of Capricorn. They cover much of Africa as well as large areas of Australia, South America, and India. They are found in tropical wet and dry climates. These areas are hot year-round, usually never dropping under 64 degrees Farenheit. Although these areas are overall very dry, they do have a season of heavy rain. Annual rainfall is from 20-50 inches per year. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur. Savannas are associated with several types of biomes. Savannas are frequently in a transitional zone between forest and desert or grassland. Savanna covers approximately 20% of the Earth’s land area.

Correct Option: C

Tropical grasslands (Savannas) are located near the equator, between the Tropic of Cancer and the Tropic of Capricorn. They cover much of Africa as well as large areas of Australia, South America, and India. They are found in tropical wet and dry climates. These areas are hot year-round, usually never dropping under 64 degrees Farenheit. Although these areas are overall very dry, they do have a season of heavy rain. Annual rainfall is from 20-50 inches per year. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur. Savannas are associated with several types of biomes. Savannas are frequently in a transitional zone between forest and desert or grassland. Savanna covers approximately 20% of the Earth’s land area.