Final answer:
The volume of the rock is the difference between the new and initial water levels in the graduated cylinder, which is 4 ml.
Step-by-step explanation:
The volume of the rock can be determined by the change in water level when the rock is submerged in the water in a graduated cylinder. When the rock is dropped into the graduated cylinder, the water level rises from 25 ml to 29 ml. This change in volume is due to the displacement of water by the rock itself, which is based on the principle that the volume of the displaced water equals the volume of the object submerged. Therefore, the volume of the rock is simply the difference in the water level before and after submerging the rock, which is 29 ml - 25 ml = 4 ml.