Final answer:
Changes in the labor force, specifically the shift in the distribution of wages and 'winner-take-all' labor markets, are key factors influencing the increasing number of poor persons in the United States.
Step-by-step explanation:
The factor that influences the growing number of poor persons in the United States is changes in the labor force. A significant issue contributing to growing inequality is the shift in the distribution of wages since the late 1970s. High-skilled laborers have seen earnings increase relative to low-skilled labor, often referred to as 'winner-take-all' labor markets. These markets have been transformed by technological advancements, increasing the demand for top-tier talent and creating substantial income gaps that are not solely based on educational differences. Additionally, growing up in poverty restricts access to quality education and services, which are essential for moving out of poverty and securing stable employment. This effect creates a cycle where those raised in poverty are less likely to find jobs that pay well, perpetuating ongoing poverty.