A temperature-time graph is shown for a material that is being heated while it is still solid. Which row correctly shows what is taking place at X, Y and Z?
- AX: boiling, Y: solid becomes hotter, Z: melting
- BX: liquid becomes hotter, Y: boiling, Z: gas becomes hotter
- CX: solid becomes hotter, Y: melting, Z: liquid becomes hotter
- DX: melting, Y: liquid becomes hotter, Z: boiling