6 The magnitude of an earthquake can be expressed numerically by using
A. only the Richter scale.
B. only the Mercalli scale.
C. both the Mercalli scale and the moment
magnitude scale.
D. both the Richter scale and the moment
magnitude scale.

are there any answer choices

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.

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.