Final answer:
Black American mothers may also have to juggle multiple shifts to support their families due to historical factors.
Step-by-step explanation:
According to the research presented, if the typical American mother has two shifts, it does not specify the typical number of shifts for a black American. However, the research does highlight that black women have historically had to accept various jobs to support their families, while black men have faced unemployment and underemployment. Therefore, it can be inferred that black American mothers may also have to juggle multiple shifts to make ends meet.