Complete the following excerpt by identifying the words that maintain logical and structural coherence across the sentences.
Answer:For decades, paleobiologists regarded the abrupt appearance of complex fauna in the early Cambrian fossil record as an evolutionary 【anomaly】, assuming that soft-bodied ancestral lineages must have diverged long before without leaving trace fossils. However, recent taphonomical analyses indicate that geochemical conditions prior to the boundary were actively 【inimical】 to organic preservation, rendering the missing fossil record an artifact of sampling rather than evidence of a sudden biological leap. Consequently, the longstanding hypothesis that Cambrian body plans emerged via an unprecedented, hyper-accelerated burst of speciation has become increasingly 【precarious】, as empirical proxies now support a far more protracted evolutionary trajectory.
Answer
Blank (i): anomaly; Blank (ii): inimical; Blank (iii): precarious.
The correct completions establish seamless logical flow across all three sentences. In sentence 1, 'anomaly' captures the perception of the Cambrian event as an unexpected deviation. In sentence 2, 'inimical' explains that harsh conditions prevented fossil preservation, framing the missing record as a geological artifact. In sentence 3, 'precarious' logically follows 'Consequently' to describe how new evidence of gradual evolution destabilizes the sudden-burst hypothesis.
Step-by-Step Solution
Key Concept
Cross-Sentence Contextual Coherence and Discourse Clues