Diagnostic Misconceptions - Analysing Caesura

Test yourself on Diagnostic Misconceptions - Analysing Caesura

• What is the effect of the caesura in this line?
  
  "Nothing beside remains. Round the decay"

• What is the effect of the caesura in these lines?
  
  

  "And wrinkled lip, and sneer of cold command,
  Tell that its sculptor well those passions read"

• Who said - "Two vast and trunkless legs of stone
  Stand in the desert...Near them, on the sand"
  
  Why does the poet use ellipses (...) to create caesura in the second line?