Final answer:
During the Romanesque period, the increase in stone sculpture production was likely caused by economic expansion, the patronage of the Catholic Church and monasteries, and the revival of classical art.
Step-by-step explanation:
During the Romanesque period, stone sculpture began to be produced again in greater numbers. This increase in stone sculpture production was most likely caused by several factors. Firstly, the expansion of towns and cities during this period led to an increase in economic activity, which created a demand for artistic works. Additionally, the growing power of the Catholic Church and the establishment of monasteries provided patronage for stone sculptors. Lastly, the revival of classical art and the influence of Byzantine and Carolingian concepts also played a role in the resurgence of stone sculpture during the Romanesque period.