Which relative dating principle states that sedimentary layers lower in a sequence are older than the sedimentary layers on top of (or overlying) them?

Ascientist observes hot water erupting from a vent in the earth. what most likely caused the water to rise and erupt from the vent? the vent was lower than the water table. a well was drilled into a pressurized aquifer. a well with a mechanical pump was installed. the water was heated by magma or hot rocks.