3. Explain the moon's effects on the tides and describe the different types of tides.
4. Explain the reasons for differences in sea level

3. High tides and low tides are caused by the Moon. The Moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the Moon and the side farthest from the Moon. ... When you're not in one of the bulges, you experience a low tide.
4. 1) As water warms and cools it expands and contracts; 2) The amount of water contained as ice on land surfaces changes over time; 3) The Earth's surface is dynamic and can move vertically. The first two reasons are directly caused by global temperature changes.