GMAT Sentence Correction (SC) | Much like humans, when male dolphins woo

Replying to a pvt. Glad to help you

well, genrally speaking Im polite but this question is a really crap. a junk

Moreover, is a question from 800 score and this source is not the best way to study for this test.

Much like humans,when male dolphins woo females, those who offer gifts to potential mates are more likely to receive a positive response.

A when male dolphins woo females, those who offer gifts to potential mates are more likely to receive a positiveresponse

who ?? which is which ?? who is used for human beings not else