millimetres (or tenths of millimetres, if you have a micrometer)
Metres.
a tape measure
pounds
A millimetre.
meters
It depends on the width of the desk. You could use centimeters or meters.
A hair is about 50 µm (microns).
Feet
It is a metre.
metres
Millimetre.
In the metric system, centimeters (cm) would be the best unit to use.
In liters
Metres.
barman curls -2
the answer is pounds
the metric system