What is the name of the supercontinent that existed approximately 300 million years ago?

The name of the supercontinent that existed approximately 300 million years ago is Pangaea. Pangaea was a massive landmass that formed during the late Paleozoic and early Mesozoic eras. Its formation marked the culmination of earlier continental collisions and the merging of various landmasses, leading to a single large continent surrounded by a vast ocean called Panthalassa. Pangaea is significant in the history of Earth because it played a crucial role in the geological and biological evolution of the planet, including climate conditions, sea level changes, and the distribution of flora and fauna.

The other options refer to different supercontinents that existed at various times in Earth's history or to specific landmasses. Gondwana was a significant landmass that comprised parts of today's southern continents before the formation of Pangaea. Laurasia was the northern part of Pangaea that eventually split into North America, Europe, and Asia. Rodinia predates Pangaea and existed around a billion years ago, indicating that while all these terms are important in understanding Earth's geological history, Pangaea specifically aligns with the timeframe of around 300 million years ago.