So I believe you are supposed to take notes based on the guiding questions (the questions on the side).
The usual units of density are g/cm.
You may have also seen g/mL used for density. Keep in mind that 1 cm = 1 mL.
Answer:

Explanation:
The two requirements for a measurement are a <u>number</u> and a <u>unit.</u>
For example, here is a measurement:
38.6 cm
The <u>number</u> is 38.6 and the <u>unit</u> is cm, or centimeters.
Therefore, both <em>number </em>and <em>unit</em> are correct.