Geologic Faults A fault is a in Earth’s .
• Rocks along a fault and .
• Faults are than the rocks that surround them.
It can be difficult to determine relative age because the rocks have moved.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.