conservation for art is "preserving, fixing, or just restoring old art or other things like artifacts etc." (found in an article on www.msaconservation.com)  it's most likely controversial because if something's old and valuable, people want to keep it in it's original form. (just a guess) but that's how it is in the art world. 
 
        
                    
             
        
        
        
Answer:
What video?
Explanation:
The colours, which are made by grinding dry-powder pigments in pure water, dry and set with the plaster to become a permanent part of the wall. Fresco painting is ideal for making murals because it lends itself to a monumental style, is durable, and has a matte surface.
 
        
             
        
        
        
Answer:
I'm almost positive its B
Explanation:
it helped projectors
 
        
             
        
        
        
Answer:
A
Explanation:
An artifact is a term associated with finding something from a different time period. It is too specific. Not B
Renaissance: is a time period were human thought developed most strongly. In the west, the thought of the church was somewhat abandoned. The answer is not C.
A pictograph is a symbol for a word or phrase. It might be described as a term refering to growth, but growth is not quite the right word.
The answer is A aesthetics. That includes any of the arts.