Which phase of water is the most dense and which is the least dense

The ice form of water is most dense, and the vapor form of water is the least dense.

Explanation:

The molecular cohesion in ice is stronger than in liquid or vapor, forcing the molecules of water to remain closely bonded making it dense.  The vapor form of water is weaker that liquid and ice since the molecules are nearly free roaming or loosely bonded making it not very dense.

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well, since there is no answer choices, i will give an answer on how it works : )

the two objects are placed together. energy will always be transferred from the hotter object to the cooler object until they are equal. hope this is close to one of the answer choices : )