D: revolves around the Earth
The reason why the moon's phases can be seen is because, with the revolving of it around Earth, our Sun is in a different position in relation to Earth. These different positions allow the Sun's light to be reflected off of a differing portion of the moon.
The reason why the moon's phases can be seen is because, with the revolving of it around Earth, our Sun is in a different position in relation to Earth. These different positions allow the Sun's light to be reflected off of a differing portion of the moon.