system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the earths first gain more layers if there is a finite amount of material?

When we learn about history we learn that layers at the bottom are older and stuff up top is newer, so it's like things just keep piling up. Where did we get the stuff then? Will we run out of stuff?
gpt
Volcanoes eject material from below the Earth's surface to the top of the Earth's surface. Dust also travels with wind and can end up halfway around the world. Additionally, CO2 from the atmosphere is fixed by plants and those are eaten by animals. They all die and end up as part of the Earth. CO2 to fuel this can come from volcanoes, the oceans, or released by erosion.