I would say <span>A) perceptual region</span>
Subsoil: This layer has normally less organic matter than the A horizon, so its colour is mainly derived from iron oxides. Iron oxides and clay minerals accumulate as a result of weathering. In a soil, where substances move down from the topsoil, this is the layer, where they accumulate.
Note: This information has been taken out of a website.
Answer:
i thing mass washing it seems to be
By observing how seismic waves are absorbed and refracted, scientist have been able to work out where the properties of the earth change dramatically. our understanding of the internal structures of the earth and the size of its core is based on these observations.
basically:
size of core
structure of the earth I.e. the layers of the earth
and I think the last one is how the internal structure is changing? not sure on the last one but its still a solid guess.
