The answer is either centimeters or millimeters.
The international (SI) unit for mass is the kilogram.
pound
An instrument called micrometer is used to measure paper or card thickness.
Kilometres are the appropriate unit.
millimeters
You would use the SI unit of length, which is the meter (m), to measure a paper clip.
Grams
The most reasonable metric unit used to measure a paper clip is the millimeter. It provides a small and precise measurement that is suitable for the size of a paper clip.
Use centimeters or millimeters.
Millimetres
inches or centimeters
grams
You would typically use grams (g) or milligrams (mg) to measure the mass of a paper clip.
There's no "correct" unit. You can use any unit of mass you like, althoughthe gram is sure to result in the most convenient final number.
The easiest way would be to have a measuring cup or graduated cylinder and pour enough water into it so that you could immerse a paper clip in the water without it sticking out. Then you drop the paper clip into the water, and measure the difference in how much is in the container. The difference between the two amounts is the volume of the paper clip.
The most appropriate metric unit measurement for the capacity of a paper cup is milliliters (mL) or cubic centimeters (cm³). These units are commonly used to measure the volume of liquids and solids in small containers like paper cups.
Decimeter