Answer
D.Experimental bias
Explanations
Experimental bias occurs when a scientist performing a research influence the results in order to portray a certain outcome.In this case,Ron unintentionally smiled when then subject was showing to act as expected.In doing so,"smiling" the subject was able to identify the correct answer.
<span>Picture 1 is an example of a linocut. Picture 2 is an example of a wood engraving.
Observations may vary, but could include the following:
Picture 1 has a lot of dark values, bold lines, and non-detailed images. With picture 1, there is either black or white, and the values are created by the thickness of the lines. With picture 2, the values change based on the detail of the engraving and the amount of ink applied. Picture 2 includes a lot of details and is a realistic portrayal of the subject (owl). The subjects in both pictures are visible and definable. Picture on is of a bull ring, with Spanish matadors and picture 2 is of an owl in a tree. Neither picture uses color.</span>
They are used to support parts of the model during printing. After printing, you remove them.