Answer:
3. elevation above sea level
Step-by-step explanation:
In Geography, topography can be defined as the shape and structure of the Earth surface. Thus, a topographic map is used to graphically describe this features.
A topographic map can be defined as an accurate and detailed graphical (two-dimensional) description, representation or records of both natural and man-made (artificial) features on the surface of the Earth.
A topographic map is a two-dimensional model that uses contour lines to represent points of equal elevation above sea level such as mountains, hills, plains, valley etc.
The two-dimensional model of a topographic map graphically represents the height of a mount and the steepness of a slope through the use of contour lines.
Contours can be defined imaginary lines used for connecting locations that are having similar elevations on the Earth's surface. These contour lines are typically used for modeling the three-dimensional shape of the Earth surface in a topographic map.
Additionally, topographic maps have various real-life applications such as hunting, surveying, fishing, camping, urban planning, hiking etc.