-2.HISTORY UNDER THE WAVES
A team of marine archaeologists led by Robert ,Ballard, an internationally renowned scientist who made headlines when he located the remains of the oceanliner Titanic in 1986, announced in 1997 yet another extraordinary discovery made in the depths of the Mediterranean Sea. Using a sophisticated nuclear submarine on loan from the United States Navy, the marine archaeologists located five ships in the depths of the Mediterranean that had sunk over a period of 2,000 years. Three of the wrecks were relatively modern. One, believed to be a relic of the Ottoman Empire, dated back to the 18th or 19th century. Two more ships, believed to be of European origin, also dated back to the 19th century, the archaeologists estimated. Two other ships discovered at the bottom of the sea, however, were believed to have originated in the classical world over two thousand years ago, when the imperial powers of Rome and Carthage dominated the region and its shipping routes. Historians unanimously praised the discovery as one that would redefine modern perceptions of trade in the ancient world.
We understand from the passage that marine archaeology ------ .
concentrates on exploring trade routes
is impossible without nuclear power
focuses more on modern history
explores underwater sites for remnants of the past
is solely concerned with retrieving treasure