Good job with that one Stephen! I think you nailed it and explained it well enough to aid her understanding :)!

"Cause" and "reason" are very similar. A "reason" explains why something happened. A "cause" is what made it happen. "The reason I was late is that there was a traffic jam." "A traffic jam caused me to be late." These mean basically the same thing. The traffic jam is both the cause of the lateness and the reason for it. Another way to say it is "I was late because of a traffic jam". A "factor" contributes to an outcome. "His intense training was a major factor in his victory." I hope that helps! Hopefully other people will answer as well.