Today, in countries where arranged marriages used to be the norm, it is more common for the children to marry only when they themselves accept their parents' choice. Unions like these are called .

Care takers union while your USA is careless union

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.