What are the things that define a culture?
Culture is defined by language, music and food.
"buy" means to purchase, whereas "by" is a preposition.
Again, your friend Traeken has made all necessary corrections. I think you will always be able to trust that he is giving you what you need.
Thank you, you are very kind. Although "always" may be too generous, I certainly make mistakes and can often do a better job (especially when I am tired). ;-)