To make sure that the results of your experiment are valid, you should do which of the follwoing?
a
ask an expert
b
conduct several trials
c
complete fewer trials. too much data can confuse the experimenter.
d
make a prediction about the results. if the prediction is accurate, then you do not need to conduct any further testing.

is this for the e2020 class

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.