Answer: The answer would be land. Think back to the dinosaur age. When the dinosaurs died, there bones would sink into the ground.
The farther they sunk, the more pressure built up around them. This would cause a lot of chemical reactions to occur.
Upon sinking into the ground, they would absorb lots of other minerals and particles. Eventually over millions of years, that pressure and those chemical reactions that took place would eventually turn the bones the bones into carbon. That is why carbon is so abundant. The most common form of carbon is coal or charcoal.
Hoped this helped.
Step-by-step explanation: