Earth has been existing for how many years now?

On what eon stromatolites, the first life forms, flourished?

What is the current eon we are in?

What is the smallest time increment in the geologic time scale?

What era did dinosaurs dominate the earth?

The Paleozoic era started with a Cambrian explosion.

On what era did trilobites appear on earth?

What are the first land organisms inhabited the earth during the paleozoic era?

What is considered the greatest extinction in the geologic time history?

Which era is considered as the "Age of Reptiles"

According to geologists and paleontologists, what is the main cause of cretaceous-paleogene extinction?

Which of the following organisms did not thrive during the cenozoic era?

On what era did Ice Age happen?

How does one era end and begin another era based on the events in the geologic time scale?