Answer:
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has two related subfields: lithostratigraphy (lithologic stratigraphy) and biostratigraphy (biologic stratigraphy).
Explanation:
hope this helps you if it does please mark brainiest
1. <span>the process started with the collapse of a nebula
The universe almost certainly didn't start from the collapse of a nebula.
2. The mantle is the middle layer.</span>
The basic theory of plate tectonics is that along seafloor spreading zones, the continents are separating from one another. As they spread apart, magma comes to the surface and becomes new continental crust. As the tectonic plates move away from spreading zones, they collide with one another.
Political map would be your best option to show which countries are part of the African nations.
