Answer:
Hey the answer is one.
Explanation:
There is a quizlet with 18 of the answers with explanations on it just type in the unit subject and this question and it should pop up.
But on a side note,
I don't know who deleted my answer last time but I was giving you a resource to use if you want to learn the full step by step explanation look on your lesson videos or ask your teacher. This site i have found lets people give one another answers so unless this person and some army is planning on stopping everyone from giving answers i think they should just stop using this site.