多选题
The origin of the theory that major geologic events may occur at
regular intervals can be traced back not to a study of volcanism or plate
tectonics but to an investigation of marine extinctions. In the early 1980's,
scientists began to look closely at the question of how these extinctions occur.
Two paleontologists, Raup and Sepkoski, compiled a master list of marine species
that died out during the past 268 million years and noted that there were brief
periods during which many species disappeared at once. These mass extinctions
occurred at surprisingly regular intervals.
Later studies
revealed that extinctions of terrestrial reptiles and mammals also occurred
periodically. {{U}}These findings, combined with the research of Raup and
Sepkoski, led scientists to hypothesize the existence of some kind of cyclically
recurring
force powerful enough to affect living things
profoundly.{{/U}} Speculation that so powerful a {{U}}
force{{/U}}
might affect geologic events as well led geologists to search for evidence of
periodicity in episodes of volcanism, seafloor spreading, and plate
movement.
The passage suggests which of the following about the
"force" highlighted in the passage?
- A. It is responsible for most of the major geologic events that have
occurred.
- B. It is responsible for most of the marine extinctions that have
occurred.
- C. Its recurrence is unlikely to be able to be predicted by
scientists.
- D. Its existence was not seriously considered by scientists before Raup and
Sepkoski did their research.
- E. Its existence was confirmed by the research of Raup and
Sepkoski.