The main rule here is: if it looks significant, it should be, otherwise you are either misleading or creating unnecessary obstacles for your viewer

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Idid the quiz. the true answers to this question is  2.michelangelo used the hatching technique of drawing parallel line close together  1.leonardo used the sfumato technique of blending and blurring chalk so edges nearly dissapear3.van gogh used a variety of expressive strokes to create different surfaces and textures. to the above answer, i got it wrong. i have copy-pasted from the question, putting the answers here.i hope this .  ~rosy67read more on -

Answer ( a ) both roland and clive are correct