Answer:
The answer is number 4
Explanation:
Cross section 4 contains evidence that a transition from a hexagonal shellfish to a more a rectangular shellfish and then to a circular shellfish may have occurred. These changes would have been gradual, as shown by the position of the fossils in each layer of the canyon.
Although the evidence provided by cross section 4 is strong, more research would be needed to prove a connection among the shellfish in the canyon, such as morphological or
