I believe Erosion is the process most likely responsible for the removal of the missing parts of the rock layers. Erosion involves the physical action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, then moved away to another location.
Riley can either change the surface area of the object or can change the slipperiness of the material.
Answer:
The heat would flow from the hot solid to the cool solid until all temperatures are near equal.