11.   He said the leading theory suggests that a slab slides down underneath another plate, heats up and releases water.

12.   He said the three leading theories were a terrorist act, catastrophic technical failure, or, as American officials surmised, an errant military missile.

13.   One leading theory is that humans will continue to encounter new or rare bugs like ebola as they encroach on once-isolated jungles and rain forests.

14.   That points to another cause, and the leading theory is that the plane was brought down by a deliberate act of the backup copilot.

15.   The leading theory is that some early investors, who paid only a few dollars a share, may have cashed in.

16.   The new observations seem to support a leading theory that galaxies grew by starting out as clumps of stars.

17.   The leading theory, says Hack, involves the tubules, which are filled with fluid.

18.   The study challenges the leading theory about the sibling effect, which suggested that the effect occurred after birth, not before.

19.   A short circuit or an unextinguished cigarette butt are the leading theories in the investigation.

20.   Doctors do not know what causes SIDS, although a leading theory suggests it involves subtle brain-stem abnormalities that block normal reflexes.