Which statement about the density of warm water is most likely correct?
warm water is more dense than cold water.
warm water is less dense than cold water.
the density is the same for warm and cold water.
the density will sometimes be higher for warm water and other times higher for cold water.

Option b. warm water is less dense than cold water.

It is due to the the effect of heat on water molecules that's why warm water tend to rise above cold ones. The molecules of the water are excited by the energy. They begin moving faster, so when they bump into one another, they bounce further away. The increase space between the fast-moving molecules decreases the density.