The various lines of evidence refine scientists’ understanding of the ancestry of Cetaceans by Fossils. So, the correct option is B.
What do you mean by Fossils?
Fossils may be defined as the preserved remains, or traces of remains, of ancient organisms. It is the dead and organic remains of past organisms.
To estimate the ancestry of Cetaceans, which are categorized under marine mammals, scientists need to study their fossils, if possible. Because fossils reveal the evolutionary history in a better way.
Therefore, the various lines of evidence refine scientists’ understanding of the ancestry of Cetaceans by Fossils.
To learn more about Fossils, refer to the link:
https://brainly.com/question/11224681
