The girl is happy, ( because, moreover) she eats cake.
because
Economics (is, are ) her favorite subject
is
The mother duck with all of her little ducklings walks to the store.( correct this run on sentence)
The mother duck, with all of her little ducklings, walks to the store.
the girls who eat cake ( are, is ) happy.
are
I went to the mall with my friends after my manager gave me my payback.( correct this run on sentence)
I went to the mall with my friends, after my manager gave me my payback.
Some of the students (is, are) gone.
are
(Since, Therefor) you're such a good student, you'll get into a good college.
since
ten pounds of chocolate (is, are) too much to eat at once.
is
The boy liked birds, ( but, also) he was afraid of cats.
but
Jan, Joelle, and Adam, are twins.they so cute.(fragment, or complete sentence)
fragment