Final answer:
The Standing Rock Sioux Tribe protested the Dakota Access Pipeline because it posed a threat to sacred sites and their water supply. This reflects broader conflicts between Indigenous rights, environmental concerns, and corporate interests.
Step-by-step explanation:
The Standing Rock Sioux Tribe protested the Dakota Access Pipeline because it would run under sacred American Indian sites and could potentially harm their water supply, as the pipeline was planned near federally governed waters that hold cultural significance. The tribe's concerns about the risk of water contamination and the destruction of sacred sites gained support from a wide coalition, including environmentalists. The protests were also fueled by a perceived disregard for Indigenous rights and sovereignty, as well as broader environmental concerns regarding fossil fuel dependency and the risks of pipeline leaks. The situation at Standing Rock became emblematic of the struggles between Indigenous rights and the interests of large corporations.