Answer: designating a marine protected area.
Step-by-step explanation:
Some of the ways that tourism has diminished regional landscape distinctiveness include the building of a fast-food restaurant by a highway exit, the addition of ski runs to a mountain side, establishment of theme parks and the design of an 18-hole golf course.
It should be noted that vital way in which tourism can promote regional landscape distinctiveness is through the promotion of conservation of natural resources by countries. In this case, the designating of a marine protected area will improve regional landscape distinctiveness.