Final answer:
A biography that uses imagined conversations and adds dramatic elements based on research is a fictionalized biography, offering a blend of factual history and creative storytelling.
Step-by-step explanation:
The type of biography based on research that uses imagined conversations to create drama is known as fictionalized biography. This genre incorporates both factual research and creative embellishments to flesh out the subject's life story. Unlike authentic biographies, which stick to verifiable facts, or autobiographies, where the subject narrates their own life, fictionalized biographies allow the writer creative freedom to explore the inner dialogues and motivations of the historical figures they are profiling. This blend of fact and fiction aims not only to inform but also to provide a more engaging, narrative-driven experience for the reader.