Final answer:
The Twenty-Fourth Amendment expanded the right to vote by abolishing poll taxes.
Step-by-step explanation:
The constitutional amendment that expanded the right to vote was the Twenty-Fourth Amendment. This amendment, ratified in 1964, abolished the use of poll taxes, which were a barrier to voting for many poor African Americans in the southern states. By eliminating this discriminatory practice, the Twenty-Fourth Amendment extended suffrage to a greater number of people.