Answer:
Superposition: The oldest is on the bottom, the youngest on top. It is the deposition of one stratum over another in which the lower strata are older.
Cross-cutting relationship: Faults, fractures are younger than the rocks they cut through.
Unconformities: missing time. An unconfromity is a gap in time in rock strata, where erosion occurs while deposition slows or stops.
Original horizontality: Sedimentary layers/lava flows are deposited in flat layers.
