Final answer:
The most significant reasons for European imperialism were economic purposes and Social Darwinism, both driving resource exploitation and providing a moral justification for European dominance over other regions.
Step-by-step explanation:
Among the numerous justifications for European imperialism, the two most significant were economic reasons and Social Darwinism. The relentless pursuit of profit drove Europeans to exploit colonies for resources, which they sent back to Europe to fuel industrial production and ensure continued economic growth. Cheap raw materials and new markets for finished goods were indispensable for the industrialized nations. At the same time, Social Darwinism provided a pseudo-scientific basis that Europeans used to rationalize their dominance, arguing it as a natural and beneficial outcome of superior civilizations prevailing over weaker ones. These motivations intertwined, demonstrating how economic imperatives were often cloaked in ideological terms to justify aggressive expansion and subjugation of non-European peoples.