Final answer:
Most of the heat lost from the Earth's interior over geologic time is transported by convection.
Step-by-step explanation:
The heat lost from the Earth's interior over geologic time is mainly transported by convection. Convection is the transfer of heat energy through the movement of fluids like liquids or gases. In the Earth's mantle, hot molten rock called magma rises towards the surface, carrying heat with it, while cooler material sinks back down, creating a continuous cycle of heat transfer.
Conduction, on the other hand, is the transfer of heat through direct contact between materials. While some heat might be conducted through rocks, it is not the primary method of heat transfer from the Earth's interior.
Radioactive decay, the process where unstable elements break down and release heat, also plays a role in contributing to the overall heat loss from the Earth's interior, but it is not the primary mode of heat transport.
Learn more about Heat transfer from the Earth's interior