Question

the passage mentions the discovery of seafloor spreading in the 1960s as a key factor in the acceptance of plate tectonics theory. how did this discovery change the understanding of continental movement? answer: a. it provided a mechanism to explain how continents could move across the earths surface. b. it showed that continents moved due to changes in the earths magnetic field. c. it proved that continents were fixed in place and did not move. d. it demonstrated that continents moved because of asteroid impacts.

Explanation:

Seafloor spreading is the process by which new oceanic crust is formed at mid - ocean ridges. This process provides a mechanism for the movement of tectonic plates on which the continents sit, thus explaining how continents can move across the Earth's surface. It disproves the idea that continents are fixed. Earth's magnetic field changes are related to magnetic striping on the seafloor but not the cause of continental movement. Asteroid impacts are not related to the mechanism of continental movement provided by seafloor spreading.

Answer:

A. It provided a mechanism to explain how continents could move across the Earth's surface.