Question

it is easier to swim in sea water as compare to river water , why?

Answer 1

It is easier to swim in sea water than in a river because, the sea water contains salt which increases the density of water and also increases its upthrust so, the body sinks less in it and we swim easily .
hope it helps you

Answer 2

the density of sea water is more dan that of river water hence if v swim in sea water , our weight being less dan the density of sea water , if floats on the surface n enables us to swim easily , while in a river water our body will be in a sunken condition