Why does exhaling (Breathing) under water make your stroke more efficient?

Frankie is having difficulty developing a friendship with histeammate curtis. whenever frankie invites curtis to hangout with him at the park, curtis always says that he's busy.what is most likely preventing a healthy relationship fromforming? a)the boys are not being generous with their time andeffort.b)the boys are not communicating.c)both boys are too busy.d)the boys are on different teams.