The fossil record shows life originated on Earth at least 3.5 billion years ago and consisted entirely of microorganisms. Paleontologists provide the strongest evidence of this conclusion through the discovery of:
A)bacterial microfossils.
B)stromatolites.
C)isotopic analysis of carbon in sedimentary rocks.
D)fossil fuels (crude oil, coal).

Question

Quizplus · Accepted Answer

Stromatolites are layered geological structures that are formed by the accumulation of microorganisms. They provide evidence that microorganisms existed on Earth at least 3.5 billion years ago, as they have been dated to this time period. Bacterial microfossils and isotopic analysis of carbon in sedimentary rocks also provide evidence of early life on Earth, but stromatolites are a more direct and easily identifiable form of evidence. Fossil fuels are not direct evidence of early life, but rather the remains of organisms that lived millions of years ago.

The Fossil Record Shows Life Originated on Earth at Least