Explanation:This question was inspired by Vasili Pankratov of the Belarus Olympiad.Students are tested on their ability to design an experiment to give the best data with difficult samples, and tojudge the quality of the resulting data.There are many copies of each mtDNA gene, and only two of each nuclear gene. Therefore, if a singlespecific gene is to be used to generate a tree, it will be easier to find a mitochondrial copy than genomiccopy in heavily degraded samples.Very long fragments are contamination. Degradation over time means only small fragments of ancientDNA survive.If the artificial fragment is not recovered during sequencing, even though it was present as a positivecontrol, then we know something inhibited the sequencing reactions.False, The tree is clearly ridiculous. It is more than likely a scientist contaminated the sample with theirown DNA.