Final answer:
The Civil War and the Great Depression were both crucial in shaping American identity. The Civil War redefined American values of freedom and unity, while the Great Depression changed public expectations of government intervention, with repercussions still visible in modern American society.
Step-by-step explanation:
Each of the events listed has played a significant role in shaping American identity. The Civil War was indeed a defining moment in American history, leading to a fundamental transformation in the nation's approach to civil rights and federal versus state power dynamics. Additionally, the Industrial Revolution propelled the United States into a new economic era, fostering massive growth and technological advancement. World War II had a profound impact on the nation's role on the global stage and its perceived identity as a world power. Lastly, the Great Depression fundamentally altered Americans' perceptions of the government's role in economic stability and social welfare.
When assessing which event significantly influenced the shaping of American identity, the Civil War stands out due to its impact on the nation's moral compass and political infrastructure, leading to a redefinition of American ideals of freedom and unity. Great Depression, the consequence of economic downfall and its influence on government intervention, also deeply affected American identity by changing public expectations of government support. Considering the extent of these shifts, evidence is still found today in politics and societal values, reflecting long-term changes initiated during these challenging periods.