Explain why it was necessary for american and french forces to surround yorktown and gloucester point across the york river.

It was necessary for American and French forces to surround Yorktown and Gloucester Point across the York River where  on September 28th, 1781, 17,000 joined Continental and French troops that were jointly commanded; on land by General George Washington, and French Lieutenant General Count de Rochambeau; and at sea by French Admiral Count de Grasse. They arrived and surrounded the British General Charles Cornwallis’ camp at Yorktown and began its siege. The action took place in Gloucester, Virginia, across the York River from British-occupied Yorktown, which was under Patriot siege. The patriot victory at Yorktown effectively ended fighting in the American colonies resulting to peace negotiations between 1782, and September 3, 1783, where the Treaty of Paris was signed to formally recognize the United States as a free and independent nation after eight years of war.

the answer is b. i did this test and got it right.

no, the constitution said nothing about adding territory. president jefferson said he had authority to make treaties so he called the purchase a treaty.