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i've been having trouble with my summer assignment questions and i cant understand to answer them.
1. explain why the author and colleagues chose to focus on 375 million year old rocks in their search for fossils.

must appreciated

Fossils had been found on rocks from 365 million years ago of Reptiles and Amphibians. Older rocks, 385 mya, show fossils of fish, no neck, with a conical head, etc. The researchers hypothesized that a transitional form would probably be found roughly in between those time periods.