It has been theorized that all of the modern continents on Earth were once part of a single continent. What scientific evidence is used to support this theory?

In 1912 Alfred Wegener German meteorologist proposed the first truly detailed and comprehensive theory of continental drift and was single continent once.

He brought together a chunk of geologic and paleontological data, Alfred W. postulated that throughout most of geologic time there was just Pangea (only one continent).

At the end of the 1960s, several American researchers, including Jack E. Oliver and Bryan L. Isacks, had integrated this notion of seabed expansion with that of drifting continents and formulated the basis of the theory of Tectonic plates. According to the last hypothesis, the surface of the Earth, or lithosphere, is composed of a series of large and rigid plates that float in a soft layer (presumably partially molten) of the mantle known as asthenosphere. Oceanic ridges occur along some of the margins of the plate. In this case, the lithospheric plates separate and the material of the ascending mantle forms a new ocean floor along the posterior edges. As the plates move away from the flanks of the ridges, they carry the continents with them.

Based on all these factors, it can be assumed that the Americas joined Europe and Africa until approximately 190 million years ago, when a rift separated them along what is now the crest of the Mid-Atlantic Mountain Range. Later movements of the plate with an average of approximately 2 cm (0.8 inches) per year have brought the continents to their current position. It seems likely, although not yet proven, that this rupture of a single land mass and the drift of its fragments is simply the last of a series of similar events throughout geological time.