BBC's security expert Frank Gardner answers your questions
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Your questions about Paris attacks answered

17 November 2015 Last updated at 18:15 GMT

A number of attacks took place in Paris, France, last Friday.

More than 120 people were killed by the extremist group that calls itself Islamic state.

Loads of you have been in touch to ask why.

Martin asked BBC security correspondent Frank Gardner to answer some of your questions about what happened.