Answer:
this is not even a art question right then y are you giving art question 
 
        
                    
             
        
        
        
Answer:
a. to draw the composition on wood panels.
Explanation:
 
        
                    
             
        
        
        
The tonic<span> in music can also refer to the chord (triad) built on the first </span>scale<span> degree. In C major, the C major triad (C-E-G) is the </span>tonic<span> triad or chord.</span>
        
             
        
        
        
Symbolic proportion is the deliberate emphasis of objects in a work of art based on its importance as a symbol. This can sometimes also mean that in an artwork where symbolic proportion is applied, religious figures tend to be "bigger" or more emphasized compared to any other element a person may see in the piece. 
The artist may have used symbolic proportion to emphasize the importance or prominence of Mary and Jesus Christ - this may be relative to any smaller objects around them in the scene. 
        
             
        
        
        
The change of colour. I see a switch in the colour and it shows different perspectives