Well we get our answers from other people and if they aren't knowledgeable in the topic their isn't much you can do. More advanced questions will typically have a smaller group of people to answer them because the majority of the population hasn't taken that level in the subject or had difficulties themselves or they typically wouldn't be on a site that answers questions. The more difficult questions may also take more time especially if the person is providing in depth answers. I for one won't answer any Chemistry questions even though I'm taking a college level course in it because it is something that I struggle with. Fear of providing wrong answers and being called out for it could also lead to people not answering these questions. Also brainly trolls who will comment on the question with nonsense answers for points to ask their own questions, in the time it takes for moderators to respond to reported answers, the questions tend to get lost far down in the results which is why you see so many difficult questions farther down. If anything brainly really needs to have options for banning users like this.
