Final answer:
The South American Plate is adjacent to the Scotia Plate at a divergent boundary, where tectonic plates are moving apart and new crust is formed.
Step-by-step explanation:
The divergent boundary between the South American Plate is notably adjacent to the Scotia Plate. Divergent boundaries are areas where tectonic plates pull apart from each other, leading to the formation of new crust. This geological process is in contrast to convergent boundaries where plates collide, such as the western margin of South America, where the Nazca Plate subducts under the South American Plate, forming the Andes Mountains.
Not all plate boundaries are the same; for example, the San Andreas Fault is a transform boundary between the Pacific Plate and the North American Plate. Meanwhile, in the rift zones such as the Mid-Atlantic Ridge, plates are separating beneath the ocean, which is similar to the divergent boundary adjacent to the South American Plate.