Answer:

1. If the scientist did not discover the 3 possible causes of plate movement, then most of the people nowadays will be uneducated about the plate movement. Also, it cannot give warning to the people of what will happen if the certain type of plate movement will happen.

2. Base on my understanding, the importance of knowing the cause of plate movement is that it gave me a chance to think what will I do if a certain plate movement will happen. For example, if the movement is convergent then, I can find a solution or a plan to what will I do next.