Which statement is true?

• A. Jm predates Ply
• B. faulting occurs after JTRej
• C. dip is upstream
• D. Ps overlies Pi

Answer: (D)

Stratigraphic relationships and the idea that younger layers lie on top of older ones. When a unit sits directly on top of another, the top unit must be younger because it was deposited after the lower one, assuming the sequence is undisturbed.

In this case, the Ps unit lies atop the Pi unit with a clear, continuous contact and no signs of faulting or erosion that would complicate the order. That placement means Ps is younger than Pi, so the statement that Ps overlies Pi is true.

The other statements would require observations that aren’t supported by the observed relationship: for example, predicting that Jm predates Ply would need a different vertical order; a faulting event after JTRej would imply a cross-cutting feature not shown; and dip direction (upstream) doesn’t by itself establish the relative age of the units.