Answer:
1) There are 8 main phases of the moon: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent.
2) A full moon occurs about once a month. (every 29.5 days to be exact)
3) The phases of the moon are caused by the light from the sun and the moon's orbit around the Earth.