A phase diagram illustrates the physical state of a substance with respect to the temperature and the pressure of the surroundings. The points plotted to draw the phase diagram are derived experimentally, and are usually plotted with temperature on the x-axis and pressure on the y-axis. A typical phase diagram is shown below in Figure-1.
From the phase diagram given in the passage, predict the likely phase change if the following changes happen. Consider point A as the current phase of substance M. What is the most likely effect on substance M, if the pressure was decreased without changing the temperature of the system?