Research response: at least 2 paragraphs, 5-8 sentences per paragraph: Is it a good idea that the U. S. has approved the release of "killer" mosquitoes to fight disease?]

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.