Final answer:
The landlord's action of refusing to rent to a black American resulting in an all-white building is an example of de facto discrimination as it stems from informal practices rather than legal mandates.
Step-by-step explanation:
A landlord's refusal to rent an apartment to a black American, which leads to an all-white building despite violating the 1964 Civil Rights Act, is an example of de facto discrimination. De facto segregation occurs without specific laws mandating it, which results from traditional behavior, cultural norms, economic factors, and other informal practices. Although not upheld by law, these actions nonetheless create patterns of segregation.
From a legal standpoint, de jure segregation refers to discriminatory practices enforced by law, which have been abolished in the United States following the Civil Rights era. Nonetheless, de facto segregation has continued in various forms, often due to ingrained societal behaviors and economic disparities, despite being in violation of antidiscrimination laws like the Civil Rights Act of 1964.