Birds' feathers appear to have evolved from dinosaur scales well over

This question is based on the usage of modifiers.

Option D can be easily eliminated as it changes the meaning of the sentence completely. By using the relative adverb ‘when’, it conveys the meaning that “birds’ feathers appear to have evolved at the time that the Chinese scientists found a fossil bird”.

Option E can also be eliminated easily because the relative pronoun ‘which’ does not have clear antecedent in the first part of the sentence. The relative pronoun can only refer to a noun immediately before the comma. There is no such noun and even if we take it that ‘which’ is referring to ‘dinosaur scales’, the sentence doesn’t make sense logically.

Option C has a tense error. The verb ‘showed’ is in the past tense, whereas the verb ‘appear’ in the non-underlined part of the sentence indicates that the sentence should be in the present tense.

Option B is wrong because of the comma splice. Two whole sentences or main clauses cannot be separated by a comma. There should be either a semi-colon or a conjunction joining the two.

Therefore, A is the best option.

Jayanthi Kumar.