Fill in the blanks. Heat, mostly from the core, drives in the mantle. This causes the warmer material to rise and the cooler to win in a continuous pattern, much of Earth's internal heat is left over from its ___ 4.6 billion years ago and the rest comes from radioactive decay. At some point, Earth will stop producing its own heat. When this occurs, the planet's interior will cool and the ___ will stop. This will eventually stop the ___.