Exercise 1 - Part 2
For questions 1-8, think of the best word that fits each gap. Use only one word in each gap. All answers must be in lowercase.
For centuries, the deep ocean remained an impenetrable mystery, largely (1) to the extreme pressure and absolute darkness. However, recent advancements in robotic technology have finally allowed scientists to glimpse this hidden world. (2) before have we possessed such detailed images of the ocean floor. Specialized unmanned submarines can now withstand conditions that (3) otherwise crush any standard vessel. What surprised researchers most was the sheer variety of life forms thriving near hydrothermal vents. (4) from being a barren desert, the deep sea is teeming with unique organisms. Many of these creatures generate their own light, a phenomenon known (5) bioluminescence. Studying them might not (6) provide clues about the origins of life on Earth, but also help in the search for extraterrestrial life. Exceptional (7) these achievements are, we have still explored less than five percent of the ocean, leaving much (8) be discovered.