Answer:
8 mL
Step-by-step explanation:
You read volume on a graduated cylinder by counting the number under the line on top of the liquid (minuscus).
Before the rock was added, the volume is 10 mL. After the rock was added, the volume is 18 mL. Subtract the two volumes to find the volume of the rock.
18 mL - 10 mL = 8 mL