Can "Зачем" be answered with "Потому что"?
I learnt зачем is answered with чтобы, but can it also be answered with потому что?
Sometimes people do that, but most of the time they, consciously or not, use it to avoid giving a straight answer. The person who asked the question wants to know the purpose of some action, while the other person just lists what made them do it instead of taking responsibility. It can be frustrating, especially when it's obvious the other person is just making excuses. Kids are especially prone to that.
People can also answer "зачем" with "потому что" when they don't really know the purpose of something but feel compelled to give an answer other than "I don't know".
In general, answering "зачем" with "потому что" is not logical as it shifts the subject. Also it's pretty annoying.
Все равно, в обычной разговорной речи такие обороты не услышать. (~Anyway in a normal conversation, you will not hear such replies) Второй ответ и вовсе режет слух/ ухо (The second answer is not very pleasant to the ear)
Не будем усложнять русский язык. "Зачем ты ходил в магазин?" - "Чтобы купить хлеб." -"За хлебом."