The term 'Reef Explorer' can be broken down into two crossword solutions: DIVER (5 letters) and Scubadiver (10 letters). A DIVER is a person who swims underwater for recreational or occupational purposes. Scuba diving is a type of diving that involves the use of self-contained underwater breathing apparatus, allowing divers to stay underwater for longer periods of time. Both divers and scuba divers explore reefs, which are underwater structures made up of coral, rocks, and sand. Reef exploration is an important part of marine conservation, as it helps scientists understand the health of the reef and its inhabitants.