In an undisturbed stack of rock layers, each containing fossils of once-living organisms, where would some evidence of the most ancient life forms most likely be found?

In the bottom layer.

Explanation:

The rule of the fossil formation is that the first layer that is formed is at the bottom of the stack. The second layer contains less organism than the first layer.

This is the principle of super position that the first layer formed will be at the bottom and the newest layer formed will be at the top of the soil in the stacking.

Hence, most of the fossils will be found in the oldest layer of the soil which means at the bottom of the soil.

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b