* Solid (ice): Water freezes at 0 degrees Celsius (32 degrees Fahrenheit).

* Liquid (water): Water can also exist as a liquid at 0 degrees Celsius, but only under specific conditions.

Here's why:

* Freezing point: The freezing point of water is the temperature at which it transitions from a liquid to a solid. This occurs at 0 degrees Celsius (32 degrees Fahrenheit).

* Melting point: The melting point of water is the temperature at which it transitions from a solid to a liquid. This also occurs at 0 degrees Celsius.

So, at 0 degrees Celsius, water can exist in either state depending on the specific conditions, like the presence of impurities or the rate of heat transfer.