How are fault lines important in the formation of fault block mountains?

The fault lines pull away from eachother and it breaks up into blocks r chunks which are either forced upwards or downwards. As hey move apart these chunks or blocks end up being stacked ontop of one another causing a fault block mountain as the fault lines have been blocked up. An example of a faultblock mountain are the Sierra nevada mountains in North America.

(i dont know how many marks this question is so you may not need that much information)

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