Answer
:All of the items that are cycled through the biosphere in biogeochemical cycles
water matter nitrogen phosphorus carbon
Homologous structures are structures that are similar in related organisms because they were inherited from a common ancestor. These structures may or may not have the same function in the descendants. They all have the same basic pattern of bones. They inherited this pattern from a common ancestor. However, their forelimbs now have different functions
The answer to this is C. The ancient fossils are a record of when shallow seas covered much of the united states. While the fossils are of organisms that are the precursors of many modern day organisms, changes in ocean geography and other factors eventually caused those older species to become extinct.
B. Echinoderms hoped this helped