Resubmission: original rationale was "Answer can also be biliverdin (FA 2022 p.384). This change makes it clear that it's looking for the end result after both metabolic steps within the macrophage. Alternatively, you could change it to "...oxidized to biliverdin which is then reduced to produce..." to make it more clear." Not sure why this was just rejected outright for using FA 2022 instead of FA 2023, 1) I think it would've been simpler to comment requesting a better resource 2) I don't know if it's reasonable to expect med students to buy a new edition of FA over one that is only a year old 3) this topic isn't really contested, the two step conversion of protoporphyrin to bilirubin to UCB is agreed by many sources (B&B - gastroenterology - bilirubin - heme metabolism, https://www.uptodate.com/contents/bilirubin-metabolism, note ID 1476667635005 and 1476669535017)
