What geological evidence could there be for the presence of an early ocean?

Volcanic degassing of volatiles, including water vapour, occurred during the early stages of crustal formation and gave rise to the atmosphere. When the surface of Earth had cooled to below 100 °C (212 °F), the hot water vapour in the atmosphere would have condensed to form the early oceans.

Explanation:

The best reason for using a temperature probe instead of a thermometer is:

to record continuous measurements over several minutes

Explanation:

A temperature device may be a device, typically, a thermometer or RTD, that has for temperature measure through an electrical signal. A thermocouple (T/C) is created from 2 dissimilar metals that generate electrical voltage in direct proportion to changes in temperature.