The crust is not one single piece. It is broken up into different plates of different sizes and shapes. This is what allows them to move and thus plate tectonics occurs.
the mantle
Mountains
It has to harden
the temperture varies
subduction is when a piece of the earths crust slides back into the mantle due to density differences
The Earths crust is approximately 650 km deep.
one and a half miles thick
Carbon
The sudden vibration in the plates inside the crust causes the earths crust to rise & fall.
mantle
The earth's crust is not stress
The percentage of Earth's crust is less than one percentage in terms of Earth's volume. The Earth's crust is actually a thin layer.