This passage is adapted from material published in 2002.
In 1971, hot on the heels of plate-tectonic theorys acceptance, J. W. Morgan suggested that hotspots-areas of intense volcanism such as Hawaii, Yellowstone, and Iceland-are fueled by plumes of hot material arising in the deep mantle and punching through the mobile shallow mantle and crust to the surface. Morgans theory was developed to explain the time-progressive trails of volcanoes associated with some hotspots and the hotspots` apparent fixity relative to one another. If the sources of the volcanism were rooted in the immobile deep mantle, they would not move relative to one another and the plates at the surface would drift above, bearing away trails of volcanism. According to a recent article by geologist G. R. Foulger, however, although hotspots do exist, they do not have time-progressive volcanic trails and are not fixed relative to one another.
For the following question, consider each of the choices separately and select all that apply. The passage suggests which of the following about the relationship between the theory of plate tectonics and Morgan`s suggestion?
A. Morgan`s suggestion indirectly helped to discredit certain aspects of the theory of drifting tectonic plates.
B. Morgan`s suggestion assumes that the theory of drifting tectonic plates is correct.
C. Evidence that contradicts Morgan`s suggestion must also, by virtue of that fact, contradict the theory of drifting tectonic plates.