Identify each statement as being most like an observation, a law, or a theory.
a. All coastal areas experience two high tides and two low tides each day.
b. The tides in Earth's oceans are caused mainly by the gravitational attraction of the moon.
c. Yesterday, high tide in San Francisco Bay occurred at 2:43 A.M. and 3:07 P.M.
d. Tides are higher at the full moon and new moon than at other times of the month.