Answer:
It would help unify the paragraph.
Step-by-step explanation:
In this paragraph, the author argues that funding for girls' and boys' sports should be equal. He gives several reasons for this, such as girls' participation, the benefits that sports bring to members of both genders and the illegality of discrimination. However, sentence 3 does not mention the topic of gender differences in any way. Therefore, by removing it, we would be able to better unify the paragraph.