Final answer:
There are two types of structural explanations for the deterioration of black urban ghettos in the 1970s and 1980s: black ghetto typology and public housing projects.
Step-by-step explanation:
The researchers developed two types of structural explanations to explain why the economic and social conditions in black urban ghettos deteriorated in the 1970s and 1980s. The first type is the black ghetto typology, which focuses on the morphological evolution of ghettos and the different methods of discrimination in the United States. The second type is the public housing projects that were designed to offer affordable housing to inner-city residents but ended up contributing to the maintenance of ethnically segregated neighborhoods.