Question

Marble is a metamorphic rock. It is formed by the alteration of ___________
A. Granite
B. Coal
C. Graphite
D. Limestone

Answer 1

Hint: Metamorphosis is a biological procedure by which an animal physically grows after birth or hatching, including a noticeable and moderately sudden change in the animal's body assembly through cell growth and diversity.

Complete answer:
Most marble shapes at convergent plate limitations where huge areas of Earth's crust are visible to local metamorphism. Some marble also shapes by interaction metamorphism when a hot magma form heats next to limestone or dolostone. Before metamorphism, the calcite in the limestone is habitually in the form of lithified fossil matter and biological wreckage. During metamorphism, this calcite recrystallizes and the consistency of the rock vagaries. In the early phases of the limestone-to-marble conversion, the calcite quartzes in the rock are very minor. In a freshly-broken hand sample, they might only be documented as a sugary vivacity of light shimmering from their tiny cleavage faces when the rock is engaged in recreation in the light. As metamorphism advances, the crystals cultivate bigger and become easily identifiable as interlacing crystals of calcite. Recrystallization disguises the unique fossils and alluvial assemblies of the limestone. It also happens without creating foliation, which usually is found in rocks that are changed by the absorbed compression of a convergent plate border. Recrystallization is what marks the parting between limestone and marble. A marble that has been visible to low stages of metamorphism will have very minor calcite crystals. The crystals become bigger as the intensity of metamorphism advances. Clay minerals in the marble will modify to micas and more multifaceted silicate assemblies as the level of metamorphism upsurges.

Thus, option (D) is correct.

Note: The name "marble" is used in a dissimilar way in the aspect of stone craft. Any crystalline carbonate rock that has an aptitude to receive a polish is called "marble." The name is occasionally used for supplementary soft rocks such as travertine, verd antique, serpentine, and some limestones.