Answer:
Agriculture is the answer
General George Marshall excelled mainly as an outstanding organizer. He was appointed as Army Chief of Staff in 1939 and was able to transform the US army which at the time was a weak force of 189,000 men equipped with antiquated and poor equipment into a powerful fighting force of over eight million well-equipped and thoroughly trained American servicemen. This expansion and modernization of the armed forces meant an increase of forty times the original size in just three years (1942). He also chose many of the outstanding American generals that were instrumental in winning the war, such as Eisenhower, Patton and Bradley. He also wrote the plans for Operation Overlord, the future invasion of Nazi-occupied France (Normandy).
Douglas MacArthur was initially very incompetent in the initial stages of the War of the Pacific. He learned about the Pearl Harbor attack and did not implement a plan to prepare for the upcoming Japanese offensive. His inaction caused the Far East Air Force to be all but eradicated after a surprise Japanese air raid. He also spread his American and Filipino forces too thin in the defense of Luzon and had to retreat calamitously, leaving enormous quantities of military materials in the hands of the invading Japanese ground and naval forces. In the middle of his flight to Australia he accepted 500,000 $ from Filipino president Quezon for his pre-war service in the Philippines. He left with his family and left all the American and Filipino soldiers in Batan become POWs of the Japanese. Then was awarded the Medal of honor in order to dismiss Japanese propaganda depicting him as an incompetent coward.
He was appointed Supreme Commander of Allied Forces in the Southwest Pacific Area in 1942. He was however able to learn from his mistakes and reorganized in order to reclaim all the lost territories. It would take him four years to reclaim Papua, New Guinea, the Philippines and was later tasked with the Occupation of japan in the end of the war.
Christopher Columbus <span>was a sailor from Genoa Italy
was convinced he could reach Asia by sailing west across the Atlantic Ocean.
He was an Italian colonizer, explorer and navigator. <span>Columbus made total four trips to the Caribbean and South America
and he opened Americas to European Colonial system.</span></span>
his name is François-Marie Arouet but his literary name is pseudonym Voltaire