The African countries can easily be described and generalized, in the sense of the whole continent, as the economies are predominantly dependent on one or two products.
That dependence on one or two products is making very big problems, and it is also a very big mistake of the governments. When there's a slight variation in the prices on the certain product, the economies are heavily influenced, often in a bed manner.
It is weird though that the African countries have orientated their economies in this way, especially because the continent is very rich in lots of natural resources.
The correct answer is - Layer 2 and layer 9 are the same relative age.
On this image we can see multiple layers that have been cut through and displaced by a fault. The layer 2 and the layer 9 despite not being at the same level, with level 2 being closer to the surface, while layer 9 deeper into the ground, we can still see signs that they actually have the same relative age.
We can notice that these two layers have the same relative age because of two things. The first thing is the index fossils, with both of these layers having the same fossils from the same geologic period. The second thing that gives us a clue is their composition which is pretty much identical, thus indicating of a same geological period.
The troposphere because it has half of all air in the Atmosphere
C. urban areas I hope the answer was right if not sorry
