Which sentence correctly revises this sentence? Until class was
dismissed and all the students poured into the hall.

you need to explain that more, your grammer just needs to be close to perfect.

i think that the quotes in paragraph 11 contribute to the development of ideas because it provides a good reasoning of the central idea of the text.

the krebs cycle and electron transport occur in the mitochondria, though other than that i would need to know more information.

the pronoun reference replaces a noun, but you have to make sure there's no room for confusion.

in the first sentence "her" could be referring to shely or to the sister. the answer there is "shelly called her sister and told her about the new baby."

in the second sentence "it" could be referring to the roof or the floor. the answer there is "since the roof leaks on the family room floor, we need to repair the roof."