Answer:
Because of the revolution of the moon about the earth.
Step-by-step explanation:
The moon is the natural satellite of the earth; which rotates about its axes and orbits around the earth. As the moon orbits the earth with respect to time, it would complete a revolution in 27.3 days.
During revolution, different phases of the moon can be observed by someone on the earth. This is due to its location at different time during the process. Therefore, Jorge was able to see different phases of the moon because of its revolution about the earth.