Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

[Q]: Paragraph- Sent 1: Imagine you are standing in a farm field in central Illinois.
Sent 2: The land is so flat you can see for miles and miles.
Sent 3: On a clear day, you might see a grain silo 20 miles away.
Sent 4: You might think to yourself, it sure is flat around here.
Sent 5: If you drive one hundred miles to the south, the landscape changes.
Sent 6: In southern Illinois, there are rolling hills.
Sent 7: Why do you think this is?
Sent 8: What could have caused these features?
Sent 9: There are no big rivers that may have eroded and deposited this material.
Sent 10: The ground is capable of supporting grass and trees, so wind erosion would not explain it.
Sent 11: To answer the question, you need to go back 12,000 years.
Sent 12: Around 12,000 years ago, a giant ice sheet covered much of the Midwest United States.
Sent 13: Springfield, Illinois, was covered by over a mile of ice.
Sent 14: Its hard to imagine a mile thick sheet of ice.
Sent 15: The massive ice sheet, called a glacier, caused the features on the land you see today.
Sent 16: Where did glaciers go?
Sent 17: Where can you see them today?
Sent 18: Glaciers are masses of flowing ice.
Question: In what part of Illinois might you be able to see a grain silo that is 20 miles away?.
[A]: Central Illinois.

[Q]: Paragraph- Sent 1: American Airlines Flight 11: FAA Awareness.
Sent 2: Although the Boston Center air traffic controller realized at an early stage that there was something wrong with American 11, he did not immediately interpret the plane's failure to respond as a sign that it had been hijacked.
Sent 3: At 8:14, when the flight failed to heed his instruction to climb to 35,000 feet, the controller repeatedly tried to raise the flight.
Sent 4: He reached out to the pilot on the emergency frequency.
Sent 5: Though there was no response, he kept trying to contact the aircraft.
Sent 6: At 8:21, American 11 turned off its transponder, immediately degrading the information available about the aircraft.
Sent 7: The controller told his supervisor that he thought something was seriously wrong with the plane, although neither suspected a hijacking.
Sent 8: The supervisor instructed the controller to follow standard procedures for handling a "no radio" aircraft.
Sent 9: The controller checked to see if American Airlines could establish communication with American 11.
Sent 10: He became even more concerned as its route changed, moving into another sector's airspace.
Sent 11: Controllers immediately began to move aircraft out of its path, and asked other aircraft in the vicinity to look for American 11.
Sent 12: At 8:24:38, the following transmission came from American 11: American 11: We have some planes.
Sent 13: Just stay quiet, and you'll be okay.
Sent 14: We are returning to the airport.
Sent 15: The controller only heard something unintelligible; he did not hear the specific words "we have some planes."Sent 16: The next transmission came seconds later: American 11: Nobody move.
Sent 17: Everything will be okay.
Sent 18: If you try to make any moves, you'll endanger yourself and the airplane.
Question: What did the controllers do when American 11 left the first controller's airspace and moved into another sector?.
[A]: Immediately began to move aircraft out of its path and asked other aircraft.

[Q]: Paragraph- Sent 1: Befitting a lush, tropical island stranded in the middle of the ocean, Madeira's origins are shrouded in mystery and fanciful legend.
Sent 2: 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.
Sent 3: 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.
Sent 4: 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.
Sent 5: 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.
Sent 6: Zarco happened upon a small volcanic archipelago 1,000 km from Lisbon.
Sent 7: Perhaps Zarco knew precisely where he was heading, having learned of the existence of Madeira from a Castilian source.
Sent 8: 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.
Sent 9: More likely, Zarco was heading for Guinea and storms forced him onto the beach of Porto Santo.
Sent 10: If so, then he was extremely fortunate, for he managed to land on the only large, sandy beach for hundreds of miles around.
Sent 11: Little wonder he subsequently named it Porto Santo (Holy Port).
Sent 12: 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.
Sent 13: They officially became the first men to set foot on the heavily forested island, naming it Ilha da Madeira, "Island of Timber.
Sent 14: " The Portuguese Crown, delighted with its first important discovery, immediately embarked on a program of colonization.
Sent 15: Zarco and Teixeira were appointed co-governors of Madeira, while Perestrelo was awarded Porto Santo.
Question: Why might a Castillian source have known about the existence of Madeira around the time Zarco was exploring?.
[A]:
Canary Island occupied busy shipping lanes for very nearly a century.