Looking at the given chart, we could see that Paleozoic era follows the Precambrian time. So, <u>Option C is the correct answer.</u>
More details:
Option A states that, ‘Scientists study fossils from the Jurassic period’. After analyzing the chart, we can say that this does not help to research about Paleozoic era since Jurassic period is in Mesozoic Era.
Option B states that, ‘Scientists observe index fossil records of the Mesozoic era’. Again, this does not help to research the start of Paleozoic era.
Option C states that, ‘Scientists examine fossil evidence during the Precambrian time’. Yes. Correct. Researching about things at the Precambrian time might help them to identify what would have happened before Paleozoic era.
Option D states that, ‘Scientists explore the emergence of mammals and humans in the Cenozoic era’. This does not help since this era just 1.6 million years ago. But Paleozoic is about 500 million years ago.
