– Xochielt Sanchez
Answer by Robert Frost:
The salt in the ocean comes from a few sources, but largely it comes from the breakdown of minerals in rocks and sediments on land, carried by rivers to the ocean.
The fresh water from the river carries a small amount of salts to the sea. Then evaporation lifts fresh water into the air, but leaves the salt in the ocean. That moisture in the air condenses and falls over land, flowing into rivers and carrying new salts to the ocean.
And over. And over. And over. So that over millions of years, the oceans have accumulated a lot of salt.