Question

What may happen if the entire crust of Earth was one plate?

Answer 1

Just a guess: If the entire crust of Earth was one plate, then Earth MAY be flat, and revolve in place either horizontally or vertically. Like I said, I’m guessing, because I have no clue how gravity would act upon this theoretical flat Earth, what it would cause.

Answer 2

Many volcanoes breaking through the earths crust. The plate wouldn’t have room to move with the conduction of lava underneath. It would be like bending your knee with a big scab. It would crack and flex up or down. In short, it wouldn’t work out very well