Answer:
The last one: dinosaur footprints preserved in mud turned to rock
Fossils have to be physical remains of an animal.
Hope this helps!
cAMP in the cytoplasm
Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.
In science, the practice of classifying organisms is called taxonomy (Taxis means arrangement and nomos mean method). The modern taxonomic system was developed by the Swedish botanist Carolus Linnaeus (1707-1778). ... To distinguish different levels of similarity, each classifying group, called taxon
