Complex sentence: Provosts are military police whose duties are policing within the Armed Forces, as opposed to Gendarmerie duties in the civilian population, It should however be noted that many countries use their gendarmerie for provost duties.
Split into simpler sentences: Provosts are military police whose duties are policing within the Armed Forces, as opposed to Gendarmerie duties in the civilian population. However, many countries use their gendarmerie for provost duties.