A team of archaeologists excavating a sedimentary rock layer come across some primitive hunting tools used by early humans. As the dig progresses, they unearth the fossilized remains of a dinosaur from another layer of the sedimentary rock. Why do these discoveries indicate that the rocks were formed over millions of years? A) Early humans appeared on Earth about a million years ago. B) Humans and dinosaurs coexisted about a million years ago. C) Dinosaurs became extinct millions of years before humans appeared. D) Humans hunted dinosaurs and were responsible for their extinction