Final answer:
Locke CA being populated by majority Chinese-Americans is a good example of ethnic enclaves that formed in cities due to immigration, providing a sense of community but also creating problems of urban congestion.
Step-by-step explanation:
The example provided in the question, where historically Locke CA was populated by majority Chinese-Americans, is a good example of ethnic enclaves that formed in cities due to immigration. These enclaves, such as Chinatown, emerged as communities within larger cities where immigrant groups could maintain their language, culture, and provide services to their fellow immigrants. These enclaves provided a sense of community but also created problems of urban congestion in poorer slums where immigrants could afford housing.