Final answer:
An anticline is a fold with the oldest rocks at the center and the youngest rocks on the outside. A syncline is a fold with the youngest rocks at the center and the oldest rocks on the outside.
Step-by-step explanation:
An anticline is a fold in the Earth's crust in which the oldest rocks are located at the center of the fold and the youngest rocks are on the outside. On the other hand, a syncline is a fold in which the youngest rocks are located at the center and the oldest rocks are on the outside.
Anticlines and synclines are common geological features that occur due to compression associated with plate tectonic convergence. They can be identified on geologic maps and in cross-sections.
For example, a syncline is often concave in shape, resembling a smile, while an anticline may appear as a dome. In terms of rock ages, the rocks get younger towards the center of a syncline and older towards the center of an anticline.