Read the paragraph and answer the following question:
You must be knowing about the high and low tides that occur regularly in the sea. The level of the sea water at any given location along sea shore increase sand decreases twice a day at regular intervals. High and low tides occur at different times at places. The level of water in sea changes because of the gravitational force exerted by the moon. Water directly under the moon gets pulled towards the moon and the level of water there goes up causing high tide at that place. At two places on the earth at `90^(@)` from the place of high tide, the level of water is minimum and low tides occur there.
How many times the sea level at the coast change?
