Which of the following are North Africa's main export commodities? A. petroleum and oil products
B. cement
C. barley and wheat
D. coal and copper

Why might a single rock layer exhibit different types of sedimentary rocks within it? view available hint(s) why might a single rock layer exhibit different types of sedimentary rocks within it? such a rock layer, termed a facies, when traced laterally represents a variety of depositional environments that formed in a sequence over time. such a rock layer, termed a facies, when traced laterally represents a single depositional environment that formed over time. such a rock layer, termed a facies, when traced vertically represents a variety of depositional environments that formed at the same time across a broad area. such a rock layer, termed a facies, when traced laterally represents a variety of depositional environments that formed at the same time across a broad area. such a rock layer, termed a facies, when traced vertically represents a variety of depositional environments that formed in a sequence over time.