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.

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.