Answer:
I hope this helps!!
Explanation:
the twins could never agree, so they would often argue. Their older sister didn't like the constant arguing, so she wore her headphones most of the time!
the twins and their older sister are nouns and you use the noun first before you use the pronoun so that the reader knows who or what the pronoun is.
I am sorry if this is wrong or doesn't help you but I hope it does