The Dawes Act of 1887 aimed primarily to assimilate Native Americans into American society by transforming the communal landholdings of tribes into individual plots owned by Native Americans. This act sought to encourage a shift from traditional tribal relations to a more individualistic approach that aligned with Euro-American agricultural practices and societal norms. The act allotted specific pieces of land to individual Native Americans, with the intention of promoting farming and integrating Native Americans into the mainstream of American life, thus eroding tribal identity and communal land use.
The other options reflect aspects of Native American history but do not accurately capture the primary motivation behind the Dawes Act. For instance, while it did inadvertently affect cultural practices and land reservations, the fundamental purpose was not to protect these cultural practices but to undermine them by promoting assimilation. Similarly, the act did not create new reservations for Native Americans; rather, it conflicted with the reservation system by seeking to individualize land ownership. Although the Dawes Act did eventually lead to some Native Americans obtaining U.S. citizenship, that was not its main intent. The focus was squarely on assimilation into American society, making this the correct answer.