Answers

2016-03-26T10:13:59+05:30
The levels of the seas keeps changing. so the level of the sea carefully measured at frequent intervals and the mean levels of the sea is calculated. tidal gauge is used to measure the raising and falling of the sea
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2016-03-27T15:17:21+05:30
Tidal gauge is used to measure the raising and falling of the sea.
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