Vellum is the correct answer i believe
I believe the answer is Post and lintel construction. (Columns).
I don’t think domes were invented.
Flying buttresses were invented for the Notre Dame Cathedral in France
Towers and spires are not likely.
I hope this helps!
The future or something that happened to them
painting highly detailed and realistic images
The Colors Orange, Violet, and green are equally Spaced from each other on the Color Wheel, they are called (secondary) colors.