ambiguous pronoun

manhhiep2509 wrote:Hi.

This is the correct sentence in question 105 of verbal review 2.

"The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye"

In my opinion, "it" refers to "human eye", and "its" refers to "infrared radiation".
I expect that a pronoun can only refer to a noun, but in the sentence "it" refers to two different nouns.

Please explain why the uses of "it" and "its" in the sentence are correct.


Thank you.

Dear manhhiep2509,
I'm happy to respond.

First of all, here's an article about pronouns that discusses this point:
https://magoosh.com/gmat/2013/gmat-pronoun-traps/

In a single phrase or clause, the same pronoun absolutely must refer to the same antecedent. In this sentence, the sentence is broken in half by a semi-colon, a very clear divider. Would the GMAT accept two different pronouns, on different sides of the divider, referring to different antecedents? That's in a gray zone. The GMAT often steers clear of gray zones of grammar, but perhaps they figure that a semi-colon is enough of a strong break that it constitutes a kind of "reset button" for the pronouns.

Does all this make sense?
Mike