Complete the text with the suitable words.

Before the invention of SCUBA only a few decades ago, few men had ever ... into the ocean and those who did couldn’t go very deep. Today however, divers all over the world enjoy the underwater experience and more and more of the oceans are being ... . Cave diving is an exciting sport that is gaining in popularity. It involves ... underwater cave systems to ... their interesting rock formations and the rich ... of marine life. Underwater caves are in fact ... with all sorts of ... life seen nowhere else in the world. They are home to anything from tiny cave ... to shrimp, lobsters and certain species of shark. It’s no surprise that despite the dangers, special training and equipment, caves are a real attraction for divers.