Question

evolution and the fossil record
the fossil record describes all of the fossils that are known to scientists and their placement within sedimentary rock. the fossil record is used to show the history of life on earth. scientists are investigating fossils found within layers at a particular location. the diagram shows the layers.
layer 1
layer 2
layer 3
layer 4
layer 5
layer 6
layer 7
layer 8
layer 9
layer 10
which best compares the fossils in layer 6 to layer 10?
a. the fossils found in layer 6 are younger and more complex than the fossils in layer 10.
b. the fossils found in layer 6 are younger and less complex than the fossils in layer 10.
c. the fossils found in layer 6 are older and less complex than the fossils in layer 10.
d. the fossils found in layer 6 are older and more complex than the fossils in layer 10.

Explanation:

In sedimentary rock layers, the principle of superposition states that lower layers are older and upper layers are younger. Layer 6 is above Layer 10, so Layer 6 is younger. Also, as time progresses (layers get younger from bottom to top), organisms tend to become more complex. So fossils in Layer 6 (younger) should be more complex than those in Layer 10 (older). Option A matches this: fossils in Layer 6 are younger and more complex than in Layer 10.

Answer:

A. The fossils found in Layer 6 are younger and more complex than the fossils in Layer 10.