It would be millimetres.
The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.
I would go with millimetres
The width of an adult thumb could be somewhere between 2-4 cm.
a millimeter
5 km
The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.The answer will depend on what characteristic of the thumb you wish to measure: length, width, mass, volume, resistance to pressure, etc.
Inches and feet measure length in standard units, in metric meters and centimeters measure length.
the metric system
cm
centimetre
A millimetre.
Kilometres
Metres, to measure its length or width, square metres to measure its area.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
The width of a pin would typically be measured in millimeters (mm).
Millimetres (or centimetres to one decimal place).
I would go with millimetres