(A) ** national defense.
(B) missionary work.
(C) spreading Christianity.
(D) gaining territory.
EXPLANATIONS BELOW
Concept note-1: -Many Americans subscribed to the concept of “Manifest Destiny, ” the belief that Providence preordained the United States to occupy as much land on the continent as possible. Some saw lucrative economic opportunities in the vast stretches of arable land and superb Pacific Coast ports.
Concept note-2: -Seeking land and better opportunities, many Americans moved to territories in the West and the South. This expansionism was a driving force in American history. During the Civil War, while the nation was torn apart, expansion came to a halt.
Concept note-3: -Both a desire for new markets for its industrial products and a belief in the racial and cultural superiority of Americans motivated the United States’ imperial mission.
Concept note-4: -The philosophy drove 19th-century U.S. territorial expansion and was used to justify the forced removal of Native Americans and other groups from their homes. The rapid expansion of the United States intensified the issue of slavery as new states were added to the Union, leading to the outbreak of the Civil War.