Military Notification and Response. Boston Center did not follow the protocol in seeking military assistance through the prescribed chain of command. In addition to notifications within the FAA, Boston Center took the initiative, at 8:34, to contact the military through the FAA's Cape Cod facility. The center also tried to contact a former alert site in Atlantic City, unaware it had been phased out. At 8:37:52, Boston Center reached NEADS. This was the first notification received by the military-at any level-that American 11 had been hijacked: FAA: Hi. Boston Center TMU [Traffic Management Unit], we have a problem here. We have a hijacked aircraft headed towards New York, and we need you guys to, we need someone to scramble some F-16s or something up there, help us out. NEADS: Is this real-world or exercise? FAA: No, this is not an exercise, not a test. NEADS ordered to battle stations the two F-15 alert aircraft at Otis Air Force Base in Falmouth, Massachusetts, 153 miles away from New York City. The air defense of America began with this call. At NEADS, the report of the hijacking was relayed immediately to Battle Commander Colonel Robert Marr. After ordering the Otis fighters to battle stations, Colonel Marr phoned Major General Larry Arnold, commanding general of the First Air Force and NORAD's Continental Region. Marr sought authorization to scramble the Otis fighters. General Arnold later recalled instructing Marr to "go ahead and scramble them, and we'll get authorities later." General Arnold then called NORAD headquarters to report. F-15 fighters were scrambled at 8:46 from Otis Air Force Base.

Question: "How many military facilities did Boston Center try to contact?"

Response: "4"

A: no

Chemical changes produce new substances. For this reason, they often cannot be undone. Some chemical changes can be reversed, sort of. To do so requires another chemical change to take place. For example, you can undo the tarnish on copper pennies by placing them in vinegar. The acid in the vinegar reacts with the tarnish. This is a chemical change that makes the pennies bright and shiny again. You can try this yourself at home to see how well it works. Other chemical changes cannot be reversed at all or may be difficult to do. Rusting is a chemical change. If metal rusts, the best you can do is to sand off the rust to get down to the shiny metal. Although the metal may now be shiny, the rust was removed. The rust was not changed back into the original metal. Some chemical reactions occur in only one direction. These reactions are called irreversible reactions. For example, you cannot change a fried egg back into a raw egg. Can you think of some other irreversible reactions related to cooking? Would you like a piece of cake?

Question: "Can chemical changes be undone?"

Response: "Not really, but you can create a new chemical change that will bring the substance back to its previous state."

A: yes

(CNN) -- English club Chelsea have completed the signing of Oriol Romeu from Spanish and European champions Barcelona. The 19-year-old is currently playing for Spain at the World Under-20 Championships in Colombia and has signed a four-year deal with last season's Premier League runners-up. The deal is worth $7 million and includes a buy back clause, set at $14 million after the first year and $21 million after the second. Romeu started his career at Barcelona's city rivals Espanyol before joining the Camp Nou academy in 2004. The midfielder, who can also play in central defence, made his debut for Barcelona in last season's Spanish Supercup match with Seville and got his first taste of league action against Deportivo in May 2010. He has played 90 minutes in both of Spain's games at the World Under-20 Championships, when they beat Costa Rica and Ecuador. Chelsea official web site confirmed the signing and said Romeu is "renowned for his strength and his expansive passing ability." Another player leaving Barcelona is Jeffren Suarez after he agreed to join Sporting Lisbon. The Portuguese outfit have paid $5 million for the 23-year-old which, like the Romeu deal, includes a buy back option. Jeffren joined Barca from Tenerife in 2004 and made his debut for the Catalan club in the 2006-07 season.

Question: "How old is Oriol Romeu?"

Response: "Twenty-three"

A:
no