Over the past decade, researchers studying the brains of sparrows have discovered that each sex uses what is called their sound control system to convert sound waves to social messages and then using them to find mates, similar to how humans use vocal sounds to communicate.
A. their sound control system to convert sound waves to social messages and then using them to find
B. their sound control system to convert sound waves to social messages and then use it for finding
C. their sound control system for converting sound waves to social messages and then using them for finding
D. its sound control system to convert sound waves to social messages and then uses them to find
E. its sound control system for converting sound waves to social messages and then using it for finding
This question is based on Pronouns and Construction.
A vertical scan of the options shows us that all the options begin with a pronoun. We have a choice of the pronouns ‘their’ and ‘its’. If we ask the question – whose sound control system? – we get the answer – each sex because it is “each sex” that uses the sound control system. Since this is a singular antecedent, the pronoun that refers to it must also be singular.
Since Options A, B, and C begin with the plural pronoun ‘their’, these options can be eliminated.
Option E contains the idiomatically inappropriate phrases – for converting and for finding. The appropriate expressions are ‘use something to convert’ and ‘use to find’.
At first sight, the participle ‘using’ seems to be parallel to the other participle ‘converting’. However, on closer examination, we see that the meaning is distorted by the use of the participle and the singular pronoun ‘it’.
The meaning conveyed by this option as it stands is – each sex uses what is called its sound control system for converting sound waves to social messages and then using it (sound control system) for finding – implying that each sex uses the sound control system to find mates. The intended meaning is that each sex uses the sound control system to convert sound waves to social messages and then uses the social messages to find mates. Since the meaning and usage are distorted in this option, Option E can be eliminated.
Option D contains the appropriate pronoun and idiomatic forms. Therefore, D is the most appropriate option.