Problem: It's possible that you could one day be asked to serve on a jury. Given the fact that testimony from so many trial witnesses (defendant, eyewitness, alibi, informant, expert, etc.) is potentially untrustworthy, (1) describe what kind of evidence (or combination of evidence) you would need in order to find someone guilty beyond a reasonable doubt, and (2) justify your response, addressing why you would want to see that evidence, and why other evidence would not be sufficient. Then, change your perspective, and (3) reflect on whether the evidence you indicated you would need for a guilty verdict is a reasonable expectation for the prosecution to present at trial. (Keep in mind that if you said "I need to DNA or I won't find anyone guilty," that means no one could be found guilty in a case where the DNA is unlikely to be left behind (e.g., arson, fraud) or where the perpetrator avoided leaving DNA evidence).