Answer:
At point A, the beginning of observations, the substance exists in a solid state.
With each passing minute energy is added to the substance.
This causes the molecules of the solid substance to vibrate more rapidly which we detect by a rise in temperature of the substance.
At point B, the temperature of the substance is 70°C.
The solid begins to melt.
At point C, the substance is completely melted or in a liquid state.
During the time from point D to point E, the liquid is vaporizing.
By point E, the substance is completely in the gas phase.
Beyond point E, the substance is still in the gas phase, but the molecules are moving faster as indicated by the increasing temperature.
Step-by-step explanation: