If ice is warmed and becomes a liquid, which type of process is it?

exothermic

spontaneous

combustion

endothermic

If ice is warmed and becomes a liquid, the process is endothermic.

The process requires heat in order to proceed. If ice stays in a very cold place, it will not melt unless it's heated. If ice is placed outside where it melts on its own, it gets the heat from the surroundings.