Should it not be, 'hon vill gå på bion'? as in 'the cinema'
You could say "Hon vill gå till bion." but that would mean that she wants to go to the cinema building, whereas "Hon vill gå på bio." means that she wants to go and see a movie.
What is the matter with "she wants to go to a cinema"?
Why "the cinema" then?
Lundgren8 wrote a little more about constructions with no article here: https://www.duolingo.com/comment/5824774
Why is "She wants to go the movies" not accepted?
No, that construction would prefer the indefinite in Swedish.
Is there something wrong with "she wants to go to the movie"? It rejected and replaced movie with "pictures"
It sounds like there's a specific movie she wants to see. As for the suggested answer, I don't agree with it, but apparently there's a dialect where pictures can refer to a movie theater.
I think it should accept 'she wants to go to the movies', which gets rejected. This would be the normal way to say this in English, 'the cinema' sounds arty and affected
So is teater more of an acting stage or is there no difference?
Yes, teater only refers to the kind with a stage and live actors, never to movie theaters. It even makes me a bit sad that you use the word 'theater' for those in English. :/
Yes I guess it is just one of those things that English adopted with the modernization of the theater. I personally have only been to an actual "teater" once in my life so it is not surprising that the meaning became less important.
How come you don't need to say 'vill ha' here? Is it because the infinitive form of 'go' replaces the 'ha'?
Think of it thus: vill ha is for objects, vill is for actions.
Ah makes sense, tack!
I find it interesting that Swedish uses the definite for "skolan" but here they use the indefinite for "bio". Any reason or is that just how it is?
I think that "She wants to go to a movie." should be accepted. I never say Go to the cinema but always go to a movie. I don't know anyone that says cinema.