1. Which has more mass, the sun or the Moon?

2. Why are the high tides very high during the new and full moon phases?

3. How are the Earth sun and moon positioned during a neap tide?

Okay for #1 the answer would be the sun because it is larger in mass than the moon.

#2 - The high tides are very high during the new and full moon phases because the centrifugal force is greater than the Moon's gravitational pull.

#3 - The Earth, Sun, and Moon are alligned during a neap tide.