Fact 1: The gravitational pull of the Moon on Earth 's oceans causes the tides.

Fact 2: High tide is when the best waves come in.

Given the two facts above, answer the question "What does the gravitational pull of the Moon on Earth 's oceans cause?" with the following options: 
- Energy.
 - two
 - waves
 - fires
 - the Sun
 - sunlight
 - rivers
 - erosion


 

   waves      