For this question, I understand the difference between the NZR and Manchester but am unsure at 2 distinct reasons as I have just one primary reason. Local area networks (LANs) employ sophisticated signal encoding techniques, in preference to the naive (0=low, 1=high) encoding technique. List 2 distinct reasons for employing the sophisticated encoding techniques. My answer: Manchester encoding (or differential Manchester encoding) have bit transitions in the middle of each bit period which act as a reference point for clock synchronisation so the signal is interpreted properly at the receiver, whereas in the naive approach the clock at the receiver may drift further apart. This prevents data interpretation errors. Is the above a correct reason, and what would be another reason?

Im guessing the other reason would be built in collision detection. As a collision of signals would result in destructive / constructive interference, which would likely remove some of the mid-bit transitions. The receiver can detect this inconsistency and assume a collision has occurred. I believe this idea was explored in the first tutorial