What describes the main characteristic of an anticline structure?

An anticline is primarily characterized by its distinct folding pattern, where rock layers arch upward, forming a convex shape. This occurs due to compressional forces within the Earth's crust that push the layers of rock upward, creating a ridge-like formation. In such structures, the oldest rock layers are typically found at the core or center of the fold, with progressively younger layers arranged outward. This upward arching is a fundamental aspect of anticlines, setting them apart from other geological structures like synclines, which involve downward folding of rock layers. Understanding this characteristic is essential for geologists, as it helps in interpreting geological history and the structural composition of the Earth's crust.