It is the second-smallest county by total area in Maryland. Notable waterways include the Choptank River and Tuckahoe Creek, as well as the man-made Williston Lake. Caroline County currently ranks seventh nationally in terms of land protected under the Ag Preservation Program.
Dry air contains roughly (by volume): All the above are relatively small, light, non-polar molecules, characteristics mimicking an ideal gas. At normal ambient conditions such as standard temperature and pressure, most real gases behave qualitatively like an ideal gas.
Natural air is actually a heterogeneous mixture. It consists of nitrogen, oxygen, and argon gases, but also contains solid particles of pollen and dust. Any mixture, whether it be homogeneous or heterogeneous, can be separated into its pure components by physical means.