What if you could drain all of Earths oceans? What would it look like? You might be really surprised. You see that the surface has two main features. It has continents and ocean basins. Continents are large land areas. These are the areas that are mostly above sea level. Ocean basins extend from the edges of continents. They include the ocean floor and Earths deep ocean trenches. You will also notice the ocean floor is not flat. It too has many Continents are much older than ocean basins. Some rocks on the continents are billions of years old. Ocean basins may only be millions of years old. Because the continents are so old, a lot has happened to them! As we view the land around us, we see landforms. Landforms are physical features on Earths surface. These features change over time, but how? There are actually two types of forces at work.

Question: "What is a landform?"

OPTIONS:
- no
- yes

Answer: "Landforms are physical features of the land around us, that appear on continents"

Response: yes

Befitting a lush, tropical island stranded in the middle of the ocean, Madeira's origins are shrouded in mystery and fanciful legend. Some claim that the archipelago is what remains of Plato's lost Atlantis, or part of a landmass that once fused the continents of Europe and America. The Portuguese Step Ashore: Recorded history of the volcanic archipelago begins in relatively recent times: 1418, just as the golden age of Portuguese discovery was erupting. Under the leadership of Henry the Navigator, caravels set out from the westernmost point of the Algarve, in southern Portugal, in search of foreign lands, fame, and wealth. Joao Goncalves Zarco, sailing in the service of Prince Henry, made the first of many famous Portuguese discoveries, which would culminate a century later in Magellan's historic circumnavigation of the globe. Zarco happened upon a small volcanic archipelago 1,000 km from Lisbon. Perhaps Zarco knew precisely where he was heading, having learned of the existence of Madeira from a Castilian source. After all, the waters of the Canary Islands, only 445 km (275 miles) to the south, had occupied busy shipping lanes for very nearly a century, and Genovese maps from the mid-14th century depict both Madeira and Porto Santo. More likely, Zarco was heading for Guinea and storms forced him onto the beach of Porto Santo. If so, then he was extremely fortunate, for he managed to land on the only large, sandy beach for hundreds of miles around. Little wonder he subsequently named it Porto Santo (Holy Port). The following year Zarco returned to claim the larger island he had seen from Porto Santo, and with him went Tristao Vaz Teixeira and Bartolomeu Perestrelo. They officially became the first men to set foot on the heavily forested island, naming it Ilha da Madeira, "Island of Timber. " The Portuguese Crown, delighted with its first important discovery, immediately embarked on a program of colonization. Zarco and Teixeira were appointed co-governors of Madeira, while Perestrelo was awarded Porto Santo.

Question: "Which tropical island is claimed by some to be part of a landmass that once fused the continents of Europe and America?"

OPTIONS:
- no
- yes

Answer: "Zarco"

Response: no

According to the radar reconstruction, American 77 reemerged as a primary target on Indianapolis Center radar scopes at 9:05, east of its last known position. The target remained in Indianapolis Center's airspace for another six minutes, then crossed into the western portion of Washington Center's airspace at 9:10. As Indianapolis Center continued searching for the aircraft, two managers and the controller responsible for American 77 looked to the west and southwest along the flight's projected path, not east-where the aircraft was now heading. Managers did not instruct other controllers at Indianapolis Center to turn on their primary radar coverage to join in the search for American 77. In sum, Indianapolis Center never saw Flight 77 turn around. By the time it reappeared in primary radar coverage, controllers had either stopped looking for the aircraft because they thought it had crashed or were looking toward the west. Although the Command Center learned Flight 77 was missing, neither it nor FAA headquarters issued an all points bulletin to surrounding centers to search for primary radar targets. American 77 traveled undetected for 36 minutes on a course heading due east for Washington, D.C. By 9:25, FAA's Herndon Command Center and FAA headquarters knew two aircraft had crashed into the World Trade Center. They knew American 77 was lost. At least some FAA officials in Boston Center and the New England Region knew that a hijacker on board American 11 had said "we have some planes." Concerns over the safety of other aircraft began to mount. A manager at the Herndon Command Center asked FAA headquarters if they wanted to order a "nationwide ground stop." While this was being discussed by executives at FAA headquarters, the Command Center ordered one at 9:25. The Command Center kept looking for American 77. At 9:21, it advised the Dulles terminal control facility, and Dulles urged its controllers to look for primary targets. At 9:32, they found one. Several of the Dulles controllers "observed a primary radar target tracking eastbound at a high rate of speed" and notified Reagan National Airport. FAA personnel at both Reagan National and Dulles airports notified the Secret Service.

Question: "Which commandments went searching for American 77"

OPTIONS:
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- yes

Answer: "Herndon Command Center"

Response: yes

Right after the Pentagon was hit, NEADS learned of another possible hijacked aircraft. It was an aircraft that in fact had not been hijacked at all. After the second World Trade Center crash, Boston Center managers recognized that both aircraft were transcontinental 767 jetliners that had departed Logan Airport. Remembering the "we have some planes" remark, Boston Center guessed that Delta 1989 might also be hijacked. Boston Center called NEADS at 9:41 and identified Delta 1989, a 767 jet that had left Logan Airport for Las Vegas, as a possible hijack. NEADS warned the FAA's Cleveland Center to watch Delta 1989. The Command Center and FAA headquarters watched it too. During the course of the morning, there were multiple erroneous reports of hijacked aircraft. The report of American 11 heading south was the first; Delta 1989 was the second. NEADS never lost track of Delta 1989, and even ordered fighter aircraft from Ohio and Michigan to intercept it. The flight never turned off its transponder. NEADS soon learned that the aircraft was not hijacked, and tracked Delta 1989 as it reversed course over Toledo, headed east, and landed in Cleveland. But another aircraft was heading toward Washington, an aircraft about which NORAD had heard nothing: United 93. United Airlines Flight 93 FAA Awareness. At 9:27, after having been in the air for 45 minutes, United 93 acknowledged a transmission from the Cleveland Center controller. This was the last normal contact the FAA had with the flight. Less than a minute later, the Cleveland controller and the pilots of aircraft in the vicinity heard "a radio transmission of unintelligible sounds of possible screaming or a struggle from an unknown origin." The controller responded, seconds later: "Somebody call Cleveland?"This was followed by a second radio transmission, with sounds of screaming.

Question: "At what time did the last normal contact between United 93 and the FAA?"

OPTIONS:
- no
- yes

Answer: "After having been in the air for 45 minutes"

Response:
yes