D layer is the last layer of the soil that is present at the bottom of other layers having the oldest layers. The bottom layer of soil is formed first and when we go up the age of soil layers decreases because it is formed after the parent soil. The fossil that is present at the bottom layer is considered as oldest fossil as compared to those fossils that are present in the above layers of that soil.
Cities grew as they became sites of industrial production, centers for banking and other financial networks, the intersections of continental trade routes, and access points for global empires. Other European cities experienced similar or even more rapid periods of growth.
