Is my friend jealous of my other friend because she’s prettier?

I am 19 and I started to hang out with two different girls at the same time, and when I introduced them to each other it turned out that they were in the same high school.
They were quite polite with each other, but only in front of me, cause I can see that they’re not truly well... friends.
One of them is a gorgeous blond who can be a model and the other is well.. below average looking.
My friend who’s below average would talk shit about my pretty friend behind her back and tell me how boring and dumb she is, and my pretty friend told me once that this girl used to bully her A LOT in high school, for nothing, and I can sense that my below average looking friend ressent her more while she’s actually very sweet and kind.
My mom told me once, that it can be because she’s jealous of my good looking friend and that’s why she hated her so much. I’m average looking so I never experienced jealousy nor did I got jealous of prettier girls, but can a girl truly resent another one just for being better looking?
Is my friend jealous of my other friend because she’s prettier?
Yes she was obviously jealous
Nah it might be something else
Select gender and age to cast your vote:
Is my friend jealous of my other friend because she’s prettier?
Post Opinion