Question

unless a series of sedimentary rock layers has been overturned, the bottom rock layer usually contains fossils has the finest texture is the oldest contains the greatest variety of minerals

Explanation:

Sedimentary rock layers form over time. Newer layers are deposited on top of older ones. So, unless overturned, the bottom layer is the oldest. Fossils can be in any layer. Texture and mineral variety aren't determined by position in an undisturbed sedimentary rock series.

Answer:

is the oldest