Question

why is sea water saline

Answer 1

After years and years of river inflow and evaporation, the salt content of the lake water built up to the present levels. The same process made the seas salty. Rivers carry dissolved salts to the ocean. Waterevaporates from the oceans to fall again as rain and to feed the rivers, but the salts remain in the ocean.

Answer 2

the sea water saline because it contains large amounts of Sodium Cloride.