So far I've taken 1, 4, and 3 in that order...I found 3 to be the most "interesting" of the three, by that I mean that I had no idea what my score was going to be at the end because there were very few "that's it" answers while there were a ton of conceptual molecular biology and DNA issues as suggested by the above posters. Interestingly I got the highest score on 3 but that's probably because it's the last one I've taken, headed to take form 2 this friday and hopefully it has more quick reflex questions instead of those ones you have to think about...hate those.