A. the distribution of sand on an ocean floor
If those are the only answers i would say mutualism
I think the answer would be 420hg=4,200,000cg
All planets have these same layers (From deepest to shallowest, inner core then the outer core, then the mantle, and lastly the crust. A good example is the Earth) that is shown in the diagram, even the sun has all the layers I just listed.
But, some planets I can think of are Mars, Venus, Moon, and the Earth of course.
Layer C. sounds like it could also represent Layer D, since they are so close.
P. S. I did my best to try to answer this.
