Question

What causes the moon's phases?
a. the rotation of the moon on its axis
b.the position of the moon each month in relation to the North Star
c.changes in how much of the sunlit side of the moon faces Earth.
d.Earth's tilt on its axis as it revolves around the sun

Answer 1

c.changes in how much of the sunlit side of the moon faces Earth.

Answer 2

The cause of the moon phases is (C) ; how much sun is on the moon.

If you think about it, this is what happens. As the moon circles within 30 days, a part of the moon is ALWAYS lit by the sun but when it's circling, the farther from the sun it is, the more LIGHT of the moon we see. When the moon is directly in front of the sun, that's when we get an eclipse.