What are the two challenges that louis faced in chapter 20 in unbroken

Flying the B-24s is dangerous business, even out of combat. Friends of Louie's die and other crews go missing often. Planes malfunction, runways are too short, and the equipment is at times insufficient for the dangerous conditions the men face. For every plane lost in combat, six were lost in these accidents.

Explanation:

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."