Final answer:
The correct use of colons in a sentence to introduce a list of items or examples is demonstrated.
Step-by-step explanation:
In the given sentence, the correct use of a colon is to introduce a list of items or examples. So, the corrected version is:
The Fourth of July parade included the following floats, which all had a patriotic theme: marching bands, clowns, jugglers, and other circus performers; and antique cars, trucks, and other vehicles.
Learn more about Correct use of colons in a sentence