Answer: an introduction to provide readers with basic information before performing the first step.
cautions to help readers avoid damage to materials resulting from performing a step incorrectly
Explanation: Just took the test
The teacher uses it and the kids use it to so that they learn how and go along with the teacher hope this helps!
JajahHaiakij is my favorite
A redshift can be described as a galaxy that is moving away form us. So the correct one is D.