Here's why:

* Strata: Refers to layers of rock.

* Limbs: The sides of a fold in rock.

* Dipping inward: The layers of rock are tilted towards the center of the fold.

* Axis: The imaginary line that runs along the center of the fold.

A syncline is a fold where the limbs dip towards each other, forming a trough-like shape.

In contrast, an anticline is a fold where the limbs dip away from each other, forming a ridge-like shape.