system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
Of the following measurements, which units relate to mass? Kilogram, microgram, pound, litre, year, kilometre and ounce.


assistant
Kilogram (kg), microgram (μg), pound (lb), and ounce (oz) are all units of mass. Kilogram and microgram are units from the metric (SI) system. Pound and ounce are units from the imperial system. Litre is a unit of volume, year is a unit of time and kilometre is a unit of distance.