Question

the names of geological eras uniformly describe phases in earths evolutionary history (e.g., phanerozoic means \abundant life\). names given to geological periods, — are of diverse origins. the permian period is named after the historical region of perm in russia, for example, while the silurian period takes its name from the celtic tribe the silures. which choice completes the text with the most logical transition? a therefore, b in turn, c on the other hand, d furthermore,

Explanation:

"On the other hand" is used to present an alternative or contrasting point. Here, it is appropriate to contrast the origin - naming of different geological periods. "Therefore" implies a cause - and - effect relationship which is not applicable. "In turn" means one after the other in a particular order. "Furthermore" is used to add more information on the same topic.

Answer:

C. on the other hand