Add spaces: EachCommissionerisassignedresponsibilityforspecificpolicyareasbythePresident.

Answer: Each Commissioner is assigned responsibility for specific policy areas by the President.

Add spaces: Theproductionofthefilmhasbeenlaidinhandsofprofessionals,whichiscleartosee.Wedohopeyou'llenjoyit.

Answer: The production of the film has been laid in hands of professionals, which is clear to see. We do hope you'll enjoy it.

Add spaces: Countlesswitnessesaremappedpromptlylikeforexampledwellingmounds,sluices,mills,dikes,lighthousesandembankmentswhicharesymbolsoftheinteractionofManwithnature.

Answer:
Countless witnesses are mapped promptly like for example dwelling mounds, sluices, mills, dikes, lighthouses and embankments which are symbols of the interaction of Man with nature.