For African Americans, the one-drop rule was a significant factor in ethnic solidarity. African Americans generally shared a common cause in society regardless of their multiracial admixture, or social/economic stratification. Additionally, African Americans found it, near, impossible to learn about their Indigenous American heritage as many family elders withheld pertinent genealogical information. Tracing the genealogy of African Americans can be a very difficult process, especially for descendants of Indigenous Americans, because African Americans who were slaves were forbidden to learn to read and write, and a majority of Indigenous Americans neither spoke English, nor read or wrote it.
What brought African Americans together?
the one-drop rule

The first real progress toward a modern understanding of nervous function, though, came from the investigations of Luigi Galvani, who discovered that a shock of static electricity applied to an exposed nerve of a dead frog could cause its leg to contract. Since that time, each major advance in understanding has followed more or less directly from the development of a new technique of investigation. Until the early years of the 20th century, the most important advances were derived from new methods for staining cells. Particularly critical was the invention of the Golgi stain, which (when correctly used) stains only a small fraction of neurons, but stains them in their entirety, including cell body, dendrites, and axon. Without such a stain, brain tissue under a microscope appears as an impenetrable tangle of protoplasmic fibers, in which it is impossible to determine any structure. In the hands of Camillo Golgi, and especially of the Spanish neuroanatomist Santiago Ramón y Cajal, the new stain revealed hundreds of distinct types of neurons, each with its own unique dendritic structure and pattern of connectivity.
Who found out that a shock of electricity to an exposed nerve of a dead frog caused contractions?
Luigi Galvani

During the early 20th century, northerners were attracted to the city, and Miami prospered during the 1920s with an increase in population and infrastructure. The legacy of Jim Crow was embedded in these developments. Miami's chief of police, H. Leslie Quigg, did not hide the fact that he, like many other white Miami police officers, was a member of the Ku Klux Klan. Unsurprisingly, these officers enforced social codes far beyond the written law. Quigg, for example, "personally and publicly beat a colored bellboy to death for speaking directly to a white woman."
What was the occupation of the African-American man killed by Quigg?
bellboy