Question

Ava had read about continental drift, and that it had now become a theory. What information caused the hypothesis of continental drift to become a theory?

a) Observations that the ocean floor plates appear to be stable and unchanging.
b) Observations that Earth appears to have plates with boundaries that are moving.
c) Observations that the lithosphere is broken apart and these plates have no boundaries.
d) Observations that explain the movements of plates in the lithosphere and predict what happens when they meet.

Answer 1

The continental drift hypothesis became a theory with the observation of moving Earth plates with boundaries, leading to the comprehensive understanding of plate tectonics, explaining geological processes.

Step-by-step explanation:

The hypothesis of continental drift became a theory based on b) Observations that Earth appears to have plates with boundaries that are moving. Scientists expanded upon Alfred Wegener's initial concept of continental drift, providing evidence for the movement and interaction of these plates, leading to the acceptance of plate tectonics as the mechanism behind continental drift.

Wegener's initial evidence included the jigsaw fit of continental coasts, matching fossils across oceans, similar mountain ranges on different continents, and paleoclimatic data suggesting continental positions near the poles or equator in the past. However, it was the understanding of seafloor spreading, the movement of the oceanic and continental crust along boundaries, and the subsequent subduction and creation of new crust that solidified continental drift into a robust theory. Further discoveries in geophysics, oceanography, and geology throughout the mid-20th century led to a comprehensive understanding of plate tectonics, cementing its status as the unifying theory in geology, explaining natural processes ranging from earthquakes to mountain building and volcanic activity.