Plasma membrane or cell membrane
Radcliffe Line
a front.
Oder River
49 Parallel
The Mason - Dixon Line
The boundary between any two different layers of sediment is called a "sedimentary contact" or "stratum contact." This contact represents a change in sediment characteristics, such as composition, texture, or depositional environment. Understanding these boundaries is crucial for interpreting the geological history recorded in sedimentary rock formations.
The Iron Curtain.
The Ottawa River forms part of the boundary between the provinces of Ontario and Québec.
Ural Mountains.
San andreas.
The Ural Mountains.
This is known as the phreatic surface or water table.