Final answer:
The Codex section of Justinian's Code contained laws of ancient Rome, legal interpretations and opinions, and treatises on governance.
Step-by-step explanation:
The Codex section of Justinian's Code contained all of the above, which includes laws of ancient Rome, legal interpretations and opinions, and treatises on governance. Justinian, the Byzantine emperor, initiated the legal project to compile and edit Roman edicts issued from the second to the sixth century CE. The Code of Justinian aimed to regulate and preserve the laws of the Roman Empire.