WHEN an Iraqi journalist threw a shoe at former US President George W.Bush at a news conference last December,the president's bodyguards quickly moved to protect him. Those bodyguards were from the US Secret Service.Their job is to protect the president.Now America's first black president Barack Obama also has the same people at his side.Here are some details about these mysterious men and women. History *The Secret Service is known today for protecting public officials and their families. However,when it began in 1865,it was started to protect money.A third to a half of all US money during the Civil War was fake  .President Abraham Lincoln created the United States Secret Service to find those responsibly. *The first 25 presidents had no special protection.That changed after President William Mckinley was murdered in 1901. Who gets protection? About 30 people get full-time protection in the United States (more in an election year). Included are: *Presidents and vice-presidents and their wives,for up to 10 years after leaving office,and their children up to age 16.Anyone can decline protection after leaving office.Richard Nixon did.  *Candidates for president and vice-president,their wives and children at a cost of $500,000 a month for 30-plus special agents  . *The Secretary of State,National Security Adviser and others.The Secret Service also protects 80 to 200 visiting foreign political leaders every year. Getting around Rules for president *Limousines   that can withstand a missile are used. *Entering and exiting are never done on a street. *Exact travel plans are kept secret. *Bulletproof reading stands for speeches are used. Agent's task *Teach the president how to wave and move. *Test his food for poison. *Use special radio channels for the police and the Secret Service. *Use X-ray checks before allowing entry to secure areas,and search bags. *Check lists of hundreds of people known to be dangerous. *Keep files on thousands of people who have made even vague threats. *Be part of counter-sniper   teams. What's the purpose of writing the passage?
To tell us how to be a bodyguard. To introduce the US Secret Service to us. To give us some information about US  presidents. To inform us of the incident at a news conference.