The correct answer is They grouped organisms by the period in which they existed.
Explanation:
The job of a paleontologist is to understand the history of life on our planet by analyzing evidence such as fossils. This work has allowed paleontologists to understand the evolution of life on Earth from simple organisms such as bacteria to complex organisms such as mammals.
Moreover, this has been possible because, through different analyses, paleontologists can group the organisms they find by the periods in which they existed and this makes possible understand better the history of life including the approximate time first organisms existed, how these changed over time and how these led to the organisms that exist today.
Answer:
They grouped organisms by the period in which they existed.
Explanation:
The other answer is right with the explanation!
