Dallas - P
Glacier mountain - N
Northeast rain forest - N
River swamp - N
Dallas is a city in Texas, so it is a political region.
Glacier mountain is a natural landform so it is a natural region.
Northeast rain forest would be a naturally occurring rain forest so it would be a natural region.
River Swamp is a natural swamp so it is a natural region.
Political regions would be more along the lines of states, cities, towns, or other things of that nature. Things that are man-made and don't naturally occur in nature.