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.
In the typical adult, 1 litre of blood can hold about 200 mL of oxygen; 1 litre of dry air has about 210 mL of oxygen. Therefore, under these conditions, the ideal ventilation perfusion ratio would be about 0.95. If one were to consider humidified air (with less oxygen), then the ideal v/q ratio would be in the vicinity of 1.0, thus leading to concept of ventilation-perfusion equality or ventilation-perfusion matching.