Question

Why it is easier to swim in the sea than in the river?

Answer 1

Answer:

When salt is dissolved in water, as it is in ocean water, that dissolved salt adds to the mass of the water and makes the water denser than it would be without salt. Because objects float better on a dense surface, they float better on salt water than fresh water. Hence it is easier to swim in the sea than in the river.

Answer 2

Answer:

because sea contain salt in high level so it has low density and high buyoncy