Given a scientific question, generate a correct answer to it.

Ex Input:
What kind of planet do we consider ceres to be?

Ex Output:
dwarf planet

Ex Input:
What states that chemical reactions occur when atoms, ions, or molecules collide?

Ex Output:
collision theory

Ex Input:
Which part of the earth is made of the rigid, brittle, solid crust and uppermost mantle?

Ex Output:
lithosphere