Question ID:PT82 S4 Q15 Passage:In the winter, ravens survive by eating carcasses; in fact, an individual raven may survive for weeks on one carcass.  Yet, according to many reports, ravens will often recruit more ravens to help eat a carcass.  This seemingly altruistic behavior struck Bernd Heinrich as being worthy of investigation.  He set up observation blinds from which he had a clear view of an open meadow in which he placed meat.  He found that the mated pair of ravens in whose territory the meadow was located laid exclusive claim to the meat; so, to avoid starvation, juvenile ravens‚ who do not yet have territories‚ had to assemble in groups large enough to drive the resident pair away from the meat. Stem:Which one of the following descriptions best fits Bernd Heinrich's study as reported in the passage above? Correct Answer Choice:BChoice A:He proposed two alternative hypotheses, each of which would explain a set of observations. Choice B:His investigation partially confirmed prior observations but led to a radical reinterpretation of those observations. Choice C:He proposed a theory and then proceeded to confirm it through observation. Choice D:He used different methods from those used in earlier studies but arrived at the same conclusion. Choice E:His investigation replicated previous studies but yielded a more limited set of observational data.