A geographic coordinate system (GCS) is used to define locations on a model of the surface of the earth. The GCS uses a network of imaginary lines (longitude and latitude) to define locations. This network is called a graticule.
C. Atmosphere - which is the one sphere that means "air" or "gasses". The other ones mean, Biosphere = "living", Lithosphere = "land", and Hydrosphere = "water"
