أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
I don't think she would be called biased unless he/she ignores the rest of the students to focus on the weak ones. The art of teaching lies on how you do it.
I don't think so because if they are weaker they need that attention to help them grow their abilities to be the same level as their classmates.