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 the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. c) its 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.

C) Its rate of mutation increases over time as organisms continue to evolve and differentiate from each other.

Explanation:

Molecular clock is the term used to describe a technique used in molecular biology that aims to clarify the time of divergence between different species through the sequence of bases of their DNAs.

Mitochondrial DNA is an excellent molecule for this technique because of its high mutation rate, which increases over time. The rate of mutation of this DNA is greater than the rate of mutation of nuclear DNA, which causes mitochondrial DNA has a large number of polymorphic regions that have been generated over time. Since the mutation rate is constant, it is possible to evaluate the time of divergence between the DNA base sequences of two species.