Final answer:
The Battle of Yorktown ended in British defeat due to critical support from the French navy, which blocked British escape routes and assisted American forces on the ground, leading to British General Cornwallis's surrender and paving the way for the end of the war and American independence.
Step-by-step explanation:
The defeat of the British at the Battle of Yorktown resulted from a combination of factors, with a crucial contribution from the French navy's support. By blocking the York River, the French naval forces, led by Admiral de Grasse, sealed the fate of British General Cornwallis and his troops, trapping them on the Yorktown peninsula. The French and American armies, commanded by the Marquis de Lafayette, General George Washington, and the Comte de Rochambeau, tightened the noose by laying siege to the British forces that September.
The significant impact of the French participation in the war on the side of the Americans, starting with the crucial alliance formed after the American victory at Saratoga, cannot be overstated. French military and naval support, alongside the leadership shown by French military leaders, was decisive in Britain's ultimate capitulation.
After this pivotal battle, the road to the Treaty of Paris and the recognition of American independence was clear, marking the end of the war between the colonies and Great Britain. The British defeat at Yorktown was a direct result of the French navy's intervention, which prevented British naval assistance and reinforcements.