Answer:
The Continental Drift Hypothesis, proposed by Alfred Wegener in 1912, suggests that the Earth's continents were once joined together as a single supercontinent called Pangaea. According to the hypothesis, Pangaea began to break apart around 200 million years ago and its pieces slowly drifted to their present positions over millions of years.
Wegener's theory was based on several lines of evidence, including the fit of the continents, the distribution of fossils, and the matching of rock types and mountain ranges across different continents. However, at the time, he was unable to explain the mechanism by which the continents moved.
In the 1960s, the theory of sea floor spreading was proposed by Harry Hess, which provided an explanation for the movement of the continents. Sea floor spreading is the process by which new oceanic crust is formed at mid-ocean ridges and then moves away from the ridge, carrying the continents with it.
According to the theory of sea floor spreading, the Earth's lithosphere (the rigid outer layer of the Earth) is divided into a series of tectonic plates that move slowly over the underlying mantle. As magma rises to the surface at mid-ocean ridges, it cools and solidifies to form new oceanic crust. As this new crust forms, it pushes the existing crust away from the ridge, causing the continents to move.
The evidence supporting the theory of sea floor spreading includes the distribution of magnetic stripes on the ocean floor, which suggest that the Earth's magnetic field has reversed itself many times in the past. These magnetic reversals are recorded in the rocks on either side of the mid-ocean ridges, providing evidence for the movement of the tectonic plates.
Overall, the Continental Drift Hypothesis and the theory of sea floor spreading provide a compelling explanation for the movement of the Earth's continents over millions of years.