What must be true about two objects if heat is flowing between them? the objects must be different temperatures. the objects must be the same temperature. the objects must both be over room temperature. the objects must both be under room temperature.

Different temperatures must be true about two objects if heat is flowing between them

Option A

Explanation:

On bringing two objects with temperature differences, heat flows from a higher temperature to a lower temperature until there is thermal equilibrium according to the second law of thermodynamics.

Just like if we connect two tanks through a pipe with different water capacities. The water flows from the tank of higher water to a lower water level until both the tanks have the same water level.

The bigger the difference of temperature between two object, the higher the rate of heat flow from the hotter object to the cooler one.  Two object, having same temperature doesn’t undergo a heat flow process.

heats surface water up

3. dark matter

empty space could also be a simple vacuum