I don't get what they mean by functions either, but it functions by, uhhhh, idk
He was so excited that his eyes sparkled with delight
The correct answer would be "The balloon pulls toward the hair, and the hair. . ."
Reason for that would be static electricity.
<span>When you rub a balloon against your hair, it causes opposite static charges to build up both on your hair and the balloon.
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These two opposite charges make the hair, and the balloon attract each other.