Rock layer samples from two separate sites are shown below. Based on the diagram, which rock layers were most likely formed at the same time ?

A ; Q and R
b : Q and Y
c : r and x
D ; R and z

The correct answer to this question is "it is not biased." The information about groundwater recorded by a student is valid when it is not biased. The results could be repeated, it should be obtained from a primary source and findings should be shared with others. Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help.