Final answer:
The most direct effect of the French and Indian War that led to the American Revolutionary War was Britain's decision to tax the American colonies to repay its war debt, which increased colonial discontent and desire for independence.
Step-by-step explanation:
The effect of the French and Indian War most responsible for starting the American Revolutionary War was Britain incurring a large debt as a result of the war. Following the 1763 Treaty of Paris, Great Britain found itself not only with increased territorial possessions but also with a significantly enlarged national debt. To manage this debt, Britain sought to tax the American colonies, leading to widespread resentment and contributing to the colonial desire for independence.
The British National Debt had nearly doubled due to the war expenditures, prompting British fiscal policies that alienated the colonies. Taxes such as the Stamp Act and the Townshend Acts were imposed, which were highly unpopular. These policies, intended to make the colonies contribute to the financial costs of the empire, were among the main catalysts for the uprising that would become the American Revolutionary War.