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