Final answer:
American colonists protested the Tea Act of 1773 primarily by boycotting tea.
Step-by-step explanation:
The most common way that American colonists protested the Tea Act of 1773 was by boycotting tea. The colonists boycotted British tea by refusing to purchase or consume it. This was a widespread and organized effort coordinated by the Committees of Correspondence. As a result, British tea-carrying ships were unable to unload their tea, leading to millions of dollars' worth of tea being held hostage in storage warehouses or rotting in ship holds.