At normal atmospheric pressure and a temperature of 0 °C, both ice and water can coexist. This is because 0 °C is the freezing point of water under standard atmospheric conditions, allowing for the phenomenon known as equilibrium between the solid (ice) and liquid (water) phases.
To elaborate, at this specific temperature, water molecules have enough energy to remain in liquid form, while some molecules are arranged in a fixed structure as solid ice. This balance between the two phases is a dynamic process, as molecules continuously transition between ice and water. Therefore, the correct answer is:
- 2. Ice and water