In a reaction, a single uncombined element replaces another element in a compound. synthesis double displacement single displacement

In   a single displacement  / replacement reaction   a  single  uncombined  element   replaces  another  element   in  a  compound.

  Single   replacement   is  type  of chemical  reaction  where  an  element  react  with   a  compound  and take   the  place  of   another element  in  that  compound.
example  of  this  type  of  reaction  is 
Zn+ 2HCl  >  Zncl2  +  H2

North atlantic current or north atlantic drift is the answer