A Paleontologist Collected Fossils in the Grand Canyon and Recorded

Multiple Choice

A paleontologist collected fossils in the Grand Canyon and recorded the following data. $\begin{array} { | l | l | } \hline \text { Fossil ID } & \text { Depth from canyon rim } \\\hline \text { PCO3 } & 1,800 \mathrm {~m} \\\hline \text { B8B } & 75 \mathrm {~m} \\\hline \text { 22RD } & 1,757 \mathrm {~m} \\\hline \text { IT-O } & 757 \mathrm {~m} \\\hline \text { GH7 } & 293 \mathrm {~m} \\\hline\end{array}$
The oldest fossil collected is ________ while the youngest fossil collected is ________.

A) B8B; PCO₃
B) PCO₃; B8B
C) 22RD; B8B
D) IT-O; 22RD