Unsupported. Sibley doesn’t say which perspective is more likely to be motivated by political and economic concerns.

Unsupported. We see in P3 that Sibley recognizes that there are many examples of populations that don’t neatly fit scientists’ classifications. Additionally, Sibley’s work was about classification of bird species in particular, not the total number of animal species. The passage doesn’t suggest that Sibley thinks that the estimated number of total animal species is accurate.

Unsupported. Sibley does recognize that scientists need to limit the number of species that are recognized, but the passage doesn’t indicate that Sibley thinks that reducing the total number of species should be the goal for taxonomic research.

Anti-supported. Sibley is a splitter, and his method compares the DNA from different species to determine relationships. Sibley’s method is based on studying genetic differences, so he wouldn’t think that the degree of genetic difference should have little bearing on species classification.

This is supported in Sibley’s writings that we see in P3. Sibley acknowledges that evolution produces all degrees of genetic differences. This means that, at some point, lines must be drawn to distinguish one species from another. This shows that, even if techniques are further refined, scientists will still need to make subjective decisions about species classification, so these disagreements are likely to persist.