Which is a way that paleontologists have contributed to humans' understanding of the history of life? A They found evidence that climate has not changed significantly. B They grouped organisms by the period in which they existed. C They discovered that the first humans lived with dinosaurs. D They learned that life has existed since Earth was created.

B. They grouped organisms by the period in which they existed.

By doing so, paleontologists have been able to form a timeline of earth’s development and the evolution of life to present day. The other answers are all incorrect as the climate has changed greatly, humans lived millions of years after the last dinosaurs died off, and life was not present on earth until long after its cosmic formation (the planet required lengthy periods of rain and climate change to begin supporting life).