Answer and Explanation:
The author introduces Dr. Jekyll as a round / dynamic character, as he has a complicated and profound personality with motivations and actions that are difficult to understand and complex thoughts in relation to himself and the world around him. Dr. Jekyll has to deal with his curiosity about his own nature and reputation, as a citizen and a respected individual. although the reader has access to his thoughts, he cannot fully understand him, but finds himself reflecting on his actions and behaviors.
Hyde, on the other hand, is presented as a static / flat character, since his personality is easily defined and with little reflection, he has no depth as he can be defined as a mean, despicable and ugly being. It has no layers that make the reader reflect and think about his actions.