Why is ocean/sea water salt water and not fresh water, & how does it always contain the same amount of salt?

Question

Serious answers please, this is an honest question.

Answer 1

Here's an excerpt that explains both:

Scientists believe that ocean salinity has remained the same for the last 1.5 billion years. The elements, ions and compounds in the ocean that we refer to as "salt" are derived from the chemical and physical breakdown of rock material on the continent. As rocks erode, elements, ions and compounds wash into streams and rivers eventually washing into the ocean. As the rock material continues to break down, salts are continually added to the oceans. However salts are continually removed from the ocean keeping salinity constant. Salts in the ocean are removed in the sea spray that splashes out of the oceans, salts become locked in sediments that are deposited on the ocean floor and salts are removed from water through biological activity.

Answer 2

Volcanic Activity at the ocean floor release the raw elements that produce the salts in the ocean.
It is pretty constant as the salts have already diffused in the water.

Answer 3

its becouse a natarul reserve by god.