Final answer:
The industrial revolution and urbanization have influenced family life over the past two centuries, leading to smaller average family sizes.
Step-by-step explanation:
A change that has influenced family life over the past two centuries is the industrial revolution and urbanization. With the industrial revolution, there was a shift from farm-based work to factory work, which led to a decrease in the need for large families. Job opportunities were concentrated in urban centers, where living space was limited, resulting in smaller average family sizes. Additionally, advancements in technology and the availability of birth control contributed to changes in family structure and the roles of women.