Which best explains how the collisions of materials in space contribute to the formation of layers in protoplanets?
A. The materials undergo decay when they collide, which results in the heating and subsequent melting and rising of materials.
B. The collisions release heat, which results in the heating and subsequent melting, sinking, and rising of materials.
C. The materials undergo decay when they collide, which results in the cooling and subsequent hardening and sinking of materials.
D. The collisions absorb heat, which results in the cooling and subsequent hardening and rising of materials.