Who is Dr. Z in the context of medical advancements? (Medium)
#1: A pioneering surgeon
#2: A fictional character
#3: A notable psychologist
#4: A famous pediatrician
What notable contribution did Dr. Z make to the field of regenerative medicine? (Expert)
#1: Development of a new tissue-engineering technique
#2: Discovery of stem cell differentiation pathways
#3: Creation of a groundbreaking artificial organ
#4: Advancement of gene therapy methods