Final answer:
Metamorphism primarily occurs in the solid state with or without the presence of fluid activity, involving recrystallization of minerals due to heat and pressure but not melting the rock. Option number 2 is correct.
Step-by-step explanation:
Metamorphism takes place in the solid state with or without fluid activity. This transformation occurs due to the interaction of heat, pressure, and sometimes chemically reactive fluids on existing rocks, leading to recrystallization without reaching the melting point of the rock. High levels of heat can emanate from nearby magma, but the temperatures involved in metamorphism are not sufficient to melt the rock (subsolidus conditions). Significant pressure contributes to metamorphism as well; this pressure can arise from the weight of overlying rocks or from tectonic forces, especially during mountain building processes.
It is also essential to understand that different types of metamorphic rocks form based on the mineralogy and texture of the starting material, or protolith. Various conditions such as regional metamorphism, which is commonly connected with mountain ranges, and contact metamorphism, which happens close to magma intrusions, dictate the nature of the metamorphic transformations that occur.