Rocks and Earth Materials

Aeolian soil is the wind deposited materials that consist primarily of sand or silt-sized particles. These materials tend to be extremely well sorted and free of coarse fragments. CaO content in such soils varies from 1.0-1.5 per cent.

Gypsum can form anywhere where the right combination of mineral elements occurs and evaporation happens. It occurs as clumps of crystals or in thick beds. Gypsum beds were formed in shallow sea basins. These geologic areas are called evaporation basins because as the climate changed from tropic to arid the water evaporated concentrating the minerals it held. Gypsum formations can also occur in tidal flats along coastlines, in lagoons, deltas, hot springs, volcanic areas, desert water tables and even on plant roots.

Weathered material is transported by agents like water and wind and eventually settles in low-lying areas known as depositional basins, where it may form sedimentary rocks.

Impurities like sand,stones and rocky material present with ores are removed by employing various processes either physical or chemical in many steps and these are known as gangue.

Dolomite is a sedimentary rock. Therefore, the incorrect match is option D

RCC is Reinforced concrete cement. It is a combination of concrete and steel to build a structure instead of using only concrete. Concrete is good in resisting compression and to gain resisting tension steel is added which has high tensile strength. To overcome the drawback of concrete, reinforced steel bars are used along with concrete.

Ironing clothes is an example of conduction because the iron must touch the clothes. Ocean currents, mantle movement, and lava lamps are all examples of convection.

Microliths were small , polished and sharp stone tools. They were marked for their fine edge. They were too small to be used by themselves and would have been set into wooden or bone handles to make composite tools. Microliths were formed from prismatic blades, using the sharp unmodified lateral edges as the cutting edge.

Crystalline rock, any rock composed entirely of crystallized minerals without glassy matter. Intrusive igneous rocks—those that congeal at depth—are virtually always crystalline, whereas extrusive igneous rocks, or volcanic rocks, may be partly to entirely glassy. Many factors influence the ability of a magma to crystallize, but the length of time during which cooling occurs is the controlling factor. Metamorphic rocks are almost always crystalline; the term crystalline schists has been applied to indicate all rocks of metamorphic origin, and thus the term crystalline rocks may be taken to mean an igneous origin. Sedimentary rocks can also be crystalline, such as the crystalline limestones precipitated directly from solution; the term is not generally applied to the clastic sediments, even though they are formed largely from the accumulation of crystalline materials.

The metals at the bottom of the activity series are the least reactive. They are often found in a free state. For example, gold, silver, platinum and copper are found in the free state. Copper and silver are also found in the combined state as their sulphide or oxide ores. The metals at the top of the activity series $(K, Na, Ca, Mg$ and $Al)$ are so reactive that they are never found in nature as free elements. The metals in the middle of the activity series $ (Zn, Fe, Pb, etc.)$ are moderately reactive. They are found in the earth’s crust mainly as oxides, sulphides or carbonates. The ores of many metals are oxides. This is because oxygen is a very reactive element and is very abundant on the earth.

A river joined by its tributaries, at approximately right angles, develops a trellis pattern. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other. The dendritic pattern develops where the river channel follows the slope of the terrain. 

Sedimentary rocks are made up of grains of sediment that have been weathered from a pre-existing rock or mineral. The grains can be big or small, they are often rounded, and are cemented together in a matrix. Sedimentary rocks may be layered and may also contain fossils.

Open system is defined as a system wherein there is free exchange of both matter and energy with the surroundings. The system has interaction with the external environment. All the systems on Earth are called as open systems. Earth is an open system for energy. 

Impervious rocks are rocks which squeeze both oil and gas between them. Petroleum is obtained deep down from these impervious rocks.

Scientific consensus suggests that life on Earth originated in the oceans (hydrosphere), where early chemical reactions in a 'primordial soup' led to the development of the first simple organisms.