In rock layers, jellyfish fossils are found lower than trilobite fossils, and trilobite fossils are found lower than ammonite fossils. what can be determined from this information?

a) trilobites existed before jellyfish and ammonites.
b) jellyfish existed before trilobites and ammonites.
c)ammonites existed before trilobites and jellyfish.
d)jellyfish, trilobites, and ammonites lived together.

B) Jellyfish existed before trilobites and ammonites. 

Fossil formation. Mountains were busy forming 5 million years ago. The Tectonic plates were moving and colliding with each other. Some of the collisions were hard enough that they pushed the sides of the continents up as they collided with each other. These formed mountains such as the Appalachian mountain range. Marine rock, volcanic rock and small pieces of the ocean floor were pushed up into folds and striations that resulted in the mountains that we know today. This is just one example of a mountain range that was formed by the collision of the earth's Tectonic plates.