which rock layer is the youngest? what type of scientist studies fossils? paleontologist archaeologist…

Brief Explanations:

For the first question, according to the principle of superposition in geology, the top - most rock layer is the youngest. In the image, layer A is the top - most. For the second question, paleontologists are scientists who study fossils. Archaeologists study human - made artifacts and human history, botanists study plants, and "fossillist" is not a standard scientific term.

Answer:

A. A A. Paleontologist