Assume that water filling a crack in a rock undergoes cycles of freezing and melting. Which of the following statement is true?
◦ Water shrinks as it freezes, causing the crack walls to be drawn closer together.
◦ Water expands as it freezes, causing the crack walls to be pushed apart.
◦ Water expands as it melts, causing the crack walls to be pushed apart.
◦ Water shrinks as it melts, causing the crack walls to be pulled closer together.