If you were measuring the elevation of a mountain, you would be measuring variation in , whereas if you were doing the same on a midocean ridge, you would be measuring variation in .
1. bathymetery, isotacy
2. topography, isotacy
3. topography, bathymetry
4. bathymetry, topography

3. topography, bathymetry

Explanation:

In order to measure the elevation of the mountain system, the study of the bathymetry is essential for the study of the high altitudes. Whereas when measuring the deep mid-oceanic trenches the methods of the bathymetry is commonly used and the lake and the sea beds can thus be easily be measured.

Answermaritime tropical;

Ansarabs took control;