Final answer:
Evidence of changing family structures in the US is shown by the increase in blended families. These families form when divorced or widowed parents with children remarry, creating a new combined family unit.
Step-by-step explanation:
The evidence of a major change in the structure of families in the US in recent years is provided by a substantial increase in the number of blended families. As society has evolved, family dynamics have transformed, moving away from the traditional 'nuclear family' model. Blended families are on the rise, especially within contexts where divorce and remarriage are common. These families are characterized by parents bringing children from previous relationships into new family units. Despite the prevalence of other family types such as single-parent households and extended families, the significant increase of blended families marks a noteworthy shift in family structure within the United States.