The six essential nutrients include carbohydrates, protein, fat, vitamins, minerals and water.
I believe that element is called
flying buttresses.
Flying buttresses support the walls of a building and given that they are quite slanted, they seem as if they are forming an arch with that particular wall they are leaned against. I've attached an image of them for you to see what I mean.
Answer: Calligraphy is the art you are referring to.
I think the answer would be a
Yes, there are 7 subcategories