Simplify the following text for a Grade 7 native English-speaking person.
Original: The term Baja Bug generally refers to an original Volkswagen Beetle modified to operate off-road ( open desert , sand dunes and beaches ) , although other versions of air-cooled Volkswagens are sometimes modified as well .
Simplified: A Baja Bug is an original Volkswagen Beetle changed so that it can operate in open desert , sand dunes and beaches . Other kinds of air-cooled Volkswagens are sometimes changed this way .