Which of the following groups gained more political participation when amendments were added to the Constitution?

Among the groups listed, African Americans gained significant political participation as a result of amendments added to the U.S. Constitution. Specifically, the 15th Amendment granted African American men the right to vote in 1870, although it took many more years of struggle to ensure those rights were fully protected and realized.

While other groups also gained rights over time, the most direct and significant changes in political participation for a specific group through Constitutional amendments primarily pertain to African Americans.