Final answer:
Flooding is not a stage of planetary evolution but rather a geological event that can occur on a planet's surface.
Step-by-step explanation:
The statement that flooding is a stage of planetary evolution where high density materials sink to the core and low density materials float to the surface is false.
While it is true that in the process of planetary differentiation, denser materials sink towards the core and lighter materials rise towards the surface, flooding refers to the overflowing of water onto normally dry land. It does not refer to the movement of materials within a planet.
Therefore, flooding is not a stage of planetary evolution but rather a geological event that can occur on a planet's surface.