Plate tectonic theory is based on ____.
A) a model in which cool material in the earth's crust rises and spreads laterally beneath the crustal plates
B) the idea that Earth's crust is fragmented into rigid crusts that are sinking slowly beneath crustal plates
C) the idea that sedimentary rock formation causes continents to drift apart slowly on their crustal plates
D) observations of ridges on the sea floor, where magma pushes the surface upwards, thus moving and pushing older rock down into a ridge at the opposite edge of the sea floor
E) evidence that severe disturbances in Earth's crust shaped the continents in a single large event

Question

Plate tectonic theory is based on ____.  
A) a model in which cool material in the earth's crust rises and spreads laterally beneath the crustal plates
B) the idea that Earth's crust is fragmented into rigid crusts that are sinking slowly beneath crustal plates
C) the idea that sedimentary rock formation causes continents to drift apart slowly on their crustal plates
D) observations of ridges on the sea floor, where magma pushes the surface upwards, thus moving and pushing older rock down into a ridge at the opposite edge of the sea floor
E) evidence that severe disturbances in Earth's crust shaped the continents in a single large event

Quizplus · Accepted Answer

Plate tectonic theory is based on observations of ridges on the sea floor, where magma pushes the surface upwards, thus moving and pushing older rock down into a ridge at the opposite edge of the sea floor. This process, known as seafloor spreading, suggests that the earth's crust is constantly moving, driven by convection currents in the mantle. Plate tectonic theory explains phenomena such as volcanoes, earthquakes, and the formation of mountain ranges.

Plate Tectonic Theory Is Based on ____