Final answer:
The difference in development between former settler colonies and former plantation colonies can be attributed to volatile mono-crop economies in the latter, as explained by Dr. McCarty.
Step-by-step explanation:
Dr. McCarty explains that former settler colonies often had better administrative capacity, infrastructure, and diversified economies compared to former plantation colonies. The difference can be attributed to a few factors, but the most relevant one is the presence of volatile mono-crop economies in former plantation colonies. These economies relied heavily on a single agricultural product, making them more susceptible to market fluctuations and economic instability. In contrast, former settler colonies had a more varied economy, with multiple industries and sectors, which contributed to their overall development and resilience.