Final answer:
Hispanic females have the longest life expectancy in the United States based on 21st century data.
Step-by-step explanation:
Based on 21st century data, the group with the longest life expectancy in the United States is Hispanic females. According to a study, the average life expectancy for Hispanic females is higher compared to other groups in the country. For instance, White males have an average life expectancy of 78.8 years, while Black males have an average life expectancy of 74.7 years. It is important to note that life expectancy can vary based on numerous factors, including healthcare access, lifestyle, and genetics.