What is the drawing technique of using dots to create degrees of shading or solidity instead of using lines

The drawing technique of using dots to create degrees of shading or solidity instead of using lines is called stippling. Your options are cross-hatching, stippling, and dotting. Cross-hatching refers to using parallel lines to create shading, so that is incorrect. Although dotting is similar to stippling, here the correct answer is still stippling, that is the technique you need.

The artist is fra angelico