Why africa is very poor continent though it is very rich in natural resource?

The image shows a sandstone formation with visible bands of different colors. what do the bands indicate about how this sedimentary rock was formed? choose two answers. a). the rock was made from more than one material. b). water was absent during the compaction and cementation process. c). sediments and other matter were deposited in layers before lithification. d). the rock was stretched horizontally by the pressure from surrounding rocks. e). layers of hot liquid in the rocks cooled and solidified at different tempatures