Question

1. which is a better estimate for the volume of a conditioner bottle?
2. 18 fluid ounces 18 gallons

Explanation:

A gallon is a very large unit of volume, typically used for large containers like fuel tanks or large water jugs. A conditioner bottle is a small, handheld container, so fluid ounces are the appropriate small unit for its volume.

Answer:

18 fluid ounces