题目选项分析

The many extant fossils yet attributed to a species suggests that our classification of extinct species is either deficient, because many unclassified species merit distinct branches on the taxonomic tree, or our method of identification is lacking, with many fossils indeed attributable to known extinct species.

The many extant fossils yet to be attributed to a species suggest either that our classification of extinct species is deficient, many unclassified species meriting distinct branches on the taxonomic tree, or that our method of identification is lacking, with many fossils indeed attributable to known extinct species.