Respuesta :

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Answer:

Here's what I get  

Explanation:

The etching gel used in many dental procedures contains  

  • 10 % to 50 % phosphoric acid in water
  • a thickening agent consisting of hydrocarbon polymers and a colloidal silica sol
  • a colouring agent such as cobalt aluminate blue spinel (CoAl₂O₄)  to make it visible on a tooth.