Traces of cultivated emmer wheat have been found among the earliest

Disclaimer: this is CR, and CR question-writers aren't worried about how their sentences would hold up in SC. Also, SC is about choosing the BEST of five different options, not analyzing a single sentence in a bubble -- so looking at a single sentence in a CR passage is a very different task from a full SC question.

That said, it's all about the timeline: when did archeologists find those traces?

The phrase "have been found" suggests that the "finding" of the traces happened between some unknown moment in the past and now, and that makes a lot of sense. Obviously the first traces were found at some specific moment in the past, and the archeologists certainly didn't discover all of those traces (throughout Europe and Asia) at the exact same moment in time.

Instead, the traces were found over some (presumably long) period of time that extends between the present moment and some moment in the past when the first traces were found. And that's exactly the timeline we want for a present perfect tense -- the action took place between (1) some moment in the past and (2) right now.

The phrase "traces are found" would imply that ALL of those traces are still there and are still being found. So did the archeologists just leave all that important evidence where they found it? Perhaps that's possible, but it makes a lot more sense to suggest that all of the different traces were found at various moments between now and some unspecified moment in the past.

I hope that helps!

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.