AnujL
GMATNinja @globalexperts
please expalin
Hello
AnujL,
We hope this finds you well.
To answer your query, this is an idiom question.
The intended meaning of this sentence is that to understand how the rocks formed in the middle Miocene period we have to examine the evidence of events that happened at different points in time, evidence that takes the form of layered patterns of the sediment.
In the context of metaphorically looking at events from different points in time, we can idiomatically and metaphorically say to "look forward and backwards".
However, a question such as this one is unlikely to appear on the GMAT; as you can see, this question is from an unknown source.
We would advise not spending too much time on this one.
We hope this helps.
All the best!
Experts' Global Team