Can't "her" and "she" be used in place of "it" here?
Technically yes they can be substituted her, though for the most part people will mean "it" when saying this sentence, though this sentence is one of the zombie deleted sentences that has already been removed from the course.
Strange. I delete my history weekly to make sure I get the latest course.
The zombie sentences are an issue with Duolingo so unfortunately deleting local files won't have any effect.