Final answer:
Cross-bedding in sedimentary rock can reveal the direction of wind or water current flow. The steep side of a ripple or dune always angles downward in the direction the water or wind was moving.
Step-by-step explanation:
Cross-bedding in sedimentary rock can provide information about the direction in which wind or water current was flowing. The steep side of a ripple or dune in cross-bedding always angles downward toward the direction the water or wind was moving. For example, if the cross-bedding shows that the steep side of the ripple is facing west, it indicates that the water or wind was moving from east to west. This information can be useful in reconstructing past environments and understanding sediment transport processes.