What can be assumed about the layers in areas 2 and 4? The layers formed from sand dunes.

The layers were originally horizontal.

The layers formed in a marine environment.

The layers were deposited in a river bed.

The layers were originally horizontal.

Explanation:

We will be correct to say that both layers 2 and 4 were originally horizontal.

As with all sedimentary beds, they are originally laid horizontally in their basin of deposition.

They both now occur in a folded structure. The fold is an anticline and it youngs  upward. Layer 2 is older than 4At the time of deposition, we can know the geometry of the beds by the principle of original horizontality. Which suggests that beds are originally laid down flat in a basin.

A