Generally speaking, yes - that is to say that the overwhelming majority of the worlds bodies of water named "Lake Something-or-other" are fresh water. Great Salt Lake in Utah is one of the notable exceptions.
Because they're not saline like the oceans. Apart from considerations of pollution, the water in the Great Lakes is as drinkable as tapwater.
An ocean always contains saltwater. A Lake rarely has saltwater - lakes most often have freshwater. Brackish water( a mixture of both fresh and salt water) can be found in streams, however.
Freshwater.
Freshwater
Lake Maracaibo is saltwater, being an estuary rather than a true lake.
freshwater
Most lakes contain freshwater. From this fact, I'm assuming it is made out of freshwater, rather than saltwater.
No, all LAKES are freshwater. OCEANS are saltwater. Lake Michigan is a freshwater lake, but the answer above is false. See, for example, http://en.wikipedia.org/wiki/Great_Salt_Lake or http://en.wikipedia.org/wiki/Lake
Fresh water
Lake Okeechobee is due to freashwater
Freash water
Saltwater but with a hint of freshwater
No. Lake water is freshwater and ocean water is saltwater.
No, all LAKES are freshwater. OCEANS are saltwater. Lake Michigan is a freshwater lake, but the answer above is false. See, for example, http://en.wikipedia.org/wiki/Great_Salt_Lake or http://en.wikipedia.org/wiki/Lake