Final answer:
Fault-block mountains are formed as a result of tension stress caused by the pulling apart of the Earth's crust.
Step-by-step explanation:
Fault-block mountains are formed as a result of tension stress. Tension stress occurs when the Earth's crust is pulled apart, causing the crust to crack and blocks of rock to move upward. As these blocks of rock move, they create fault lines, and over time, these fault lines can uplift to form mountains.
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