Why dose free movement and no internal borders pose a problem to security for the EU?

Reading graphs: unemployment us unemployment rate (1961-2011) identify the trends in the graph and then use the drop- down menu to complete each statement from 1961 to 1965 unemployment was in the mid-2000s through 2011. unemployment was percentage unemployed 1961 1971 1981 1991 2001 2011 year

Crisis in rivalries between the serbs, croatians and muslims has been going on for centuries and only intensified during the 1990s when non-communist rulers were elected

Look at the map above. which of the following statement is true