Final answer:
The speaker acknowledges the historical fight against systemic racism as a testament to achieving the impossible within American Negro history, highlighting the enduring quest for acknowledgment, opportunity, and equality.
Step-by-step explanation:
The speaker believes that the historical aspect which testifies to the perpetual achievement of the impossible in American Negro history is The recognition and dismantling of systemic racism in society (D). This interpretation is modeled by the continuous struggle against racism and the quest for equal rights, seeking to harmonize a 'double self' into a united identity of being both a Negro and an American, respected and equal, without the barriers of prejudice and systematic humiliation.
Throughout history, African Americans have sought to merge their cultural heritage with their American citizenship, facing nameless prejudice while striving for equal opportunities in the fabric of U.S. society. The impossibility lies in confronting a pervasive racial bias that has relegated the black community to a second-class status despite their efforts for progress and equality. The history of African Americans reflects a deep resilience and a steadfast refusal to accept discouragement, no matter how persistent the societal barriers erected by racism.