Wich of the following is not one of the eight most common elements in earths continental crust

The similarities of organisms in which two areas numbered above provide the best evidence for common ancestry between organisms in both locations?

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

Number and variety of living organisms includes genetic, species, and ecological types