Q: What is the measure of how closely molecules are packed together?


Read this paragraph and choose the correct option from the provided answers:

Density is mass per unit volume. Density is a measure of how closely molecules are packed together. The closer together they are, the greater the density. Since air is a gas, the molecules can pack tightly or spread out.

 Choices:

- length

- volume

- frequency

- density


A:
density