Acube measures 1.0 cm on each side. what is the volume of the cube? if this cube is dropped into 28.0 ml of water, what will be the new volume reading on the graduated cylinder?

The volume of the cube is 1.0cm x 1.0cm x 1.0cm =  1.0 cm3. If this cube is dropped into 28.0 mL of water, the new volume reading on the graduated cylinder will be 29.0 mL.
1 cm3 = 1 mL
The cube will displace a volume of water equal to its own. That's why the liquid level will rise.