Answer:
The conditions of the pressure and the temperature where all the phases coexists.
Explanations:
A phase diagram is a diagram that shows the point where all the phases of matter coexists at equilibrium. This phase digram consists of the melting-freezing line, sublimation-deposition line and the
The point where all these lines coexists in equilibrium or intersects is known as the triple point.
he triple point is as marked in the diagram below;
