Unless a series of sedimentary rock layers has been overturned, which layer is usually the oldest?

the layer on the top. the layer with the most minerals.

The bottom layer.

Explanation: The oldest layers are located at the bottom of the sedimentary rock while the youngest layers are found at the top of the rock. Sedimentary rock most times contains a lot of fossils, they constitute of organisms that have once-lived.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.

the supermassive black hole is in the middle of the galaxy.