The down fold in a rock is known as a/an:

Correct option is D

The correct answer is (d) syncline.
· A syncline is a geological term for a downward fold in rock layers. In a syncline, the youngest rock layers are found at the core, with older layers progressively outward.
· It is the opposite of an anticline, which is an upward fold.
Information Booster:
· Backline: This term is not commonly used in geology and does not refer to a fold in rock layers.
· Anticline: An anticline is an upward arching fold in rock layers, with the oldest layers at the core.
· Crestline: This term typically refers to the highest point of a wave or ridge.