La is feminine so the girl is done la fille. You only use l' if the is in front of a word starting with a vowel.
Robe is female while book is male so tge have the correct corresponding un or une.
And yes has is a.
in the practice session once i placed UN LIVRE and second time i placed UNE LIVRE and i got myself wrong both times. Is there any problem in my understanding or it's an issue?(shouldn't the answer be un livre?)