The correct option is 2 only
Explanation
Alfred Wegener proposed the Continental Drift Theory in 1912. While he provided extensive evidence to support the unity and subsequent breakup of the supercontinent Pangea, the forces he suggested to explain the movement of continents were considered the weakest aspect of his theory and were initially rejected by the scientific community.
Statement-wise Analysis:
- Statement 1 is Incorrect: Wegener proposed the "pole-fleeing force" (Polflucht) as a primary driver of continental movement. This force relates to the rotation of the Earth. Because the Earth is not a perfect sphere but has a bulge at the equator, Wegener hypothesized that the associated centrifugal force caused continents to drift from the higher latitudes toward the equator.
- Statement 2 is Correct: The theory of convection currents in the mantle was not proposed by Alfred Wegener. It was introduced by Arthur Holmes in the 1930s to provide a plausible mechanism for drift, addressing the inadequacies of Wegener's proposed forces. Wegener's theory lacked this explanation.
- Statement 3 is Incorrect: Wegener attributed the westward drift of continents to the tidal force. He argued that the gravitational attraction of the Moon and the Sun (which causes ocean tides) exerted a drag on the Earth's crust as it rotated. He did not cite the gravitational pull of Jupiter as a force responsible for continental drift.
Key Takeaway:
According to Alfred Wegener, the two specific forces responsible for continental drift were the pole-fleeing force (due to Earth's rotation/shape) and the tidal force (due to the attraction of the Moon and Sun). Mantle convection is a later concept associated with Arthur Holmes and Plate Tectonics.