High and low tides are the cyclic rising and falling of the earth’s ocean surface due to the tidal forces of the moon and sun. tides change the sea depth and produce oscillating currents known as tidal streams. these streams are important for coastal navigation. the changing tide is relevant to the changing positions of the sun and moon coupled with the effects of the rotating earth and the local bathymetry. the gravitational force exerted by the sun is nearly 200 times that of the moon. however, the tidal force produced by the moon is about twice as strong as that produced by the sun. this is because the tidal force is related more to the gradient then the gravitational pull. main idea: high and low tides are the cyclic rising and falling of the earth’s ocean surface due to tidal forces of the moon and sun. which detail from the passage best supports the main idea?