The Persian Gulf is saltwater, not freshwater.
saltwater freshwater saltwater freshwater
they are both saltwater and freshwater
They contain saltwater and freshwater
Freshwater
freshwater
Freshwater.
Most lakes contain freshwater. From this fact, I'm assuming it is made out of freshwater, rather than saltwater.
the densities are different (Saltwater has a greater density than freshwater.)
An estuary is the place where freshwater and saltwater meet.
In a freshwater environment it is clean and in a saltwater it has salt.
Islands exist in both bodies of saltwater and bodies of freshwater.