Concept:An anticline is a type of fold where rock layers bend upward into an arch shape due to compressional forces in the Earth's crust.
Explanation:Folds result from ductile deformation of rock layers under stress.
An anticline is recognized by its convex upward curvature.
The oldest rock layers are exposed at the core (center) of the anticline.
The topmost point of the arch is called the crest.
Anticlines can range from small hills to large mountain ranges.
In contrast, a syncline is a downward fold (concave upward).
Graben and horst are not folds but fault blocks: a graben is a down-dropped block, a horst is an uplifted block, bounded by faults.
Therefore, for an up fold in rock, anticline is correct.
Answer:Anticline.