Both the continental drift theory and the tectonic plate theory primarily explain the phenomenon of how supercontinents in geologic history broke up and formed smaller continents.
Continental drift, initially proposed by Alfred Wegener, suggested that continents were once joined together in a supercontinent called Pangaea and have since drifted apart. The tectonic plate theory further elaborates on Wegener’s ideas by explaining that the Earth's lithosphere is divided into tectonic plates that move over the asthenosphere, leading to the formation and breakup of supercontinents, as well as various geological phenomena including earthquakes, volcanic activity, and the creation of mountain ranges.