Liz is Andrea's eight or nine year old little sister, who loves chemistry. She is a member of the Junior Science Club which Olivia teaches.
Andrea tried to encourage Liz to be like her and become a musical performer or star, but Liz became more interested in Olivia's science experiments instead. So then, Andrea accepted it's okay if her little sister isn't like her. This happened after Liz helped all the friends in Sister Act.
In Season 2, Liz starts making apps for tablets and smartphones, examples of apps she has created are StalkTalk for plants and Mearff for animal-human translation.
As revealed in Secret Friend , she doesn’t like getting distracted with her work when she moves the girls away. She also likes to make fun of her older sister as seen in Escape from Trash Island, she describes the load of trash like someone cleared out her sister's room and threw it in the bay.
In one of the magazines, on the beach the girls meet a blue-eyed girl with blonde short hair, and Liz notes it's her friend Analise.