I think the answer is evolution.
Yes, all ecosystems need to have a top predator (quaternary consumers) so that the cycle of the food chain can stay complete.
Because it's where they live.
Answer:
I don't remember much, but I'll try my best.
Explanation:
Over time, sediments rocks pile up to form horizontal layers of sedimentary rocks. The bottom layer of rock forms first, which means it's the oldest. This would mean that while you can't be sure when each layer of sediments formed, each layer is younger than the one below it.
Earthquakes only happen in certain areas of the world
