What units are used to measure shorter length?

Answer 1

millimetres, and fractions of an inch.

microscopic levels are microns or micrometres (1/1,000,000 of a metre), nanometres (1/1,000,000,000 of a metre), and picometres (1/1,000,000,000,000 of a metre)

Answer 2

The international standard for measurement is the metric meter. For very small distances the unit would be a 'nanometer' equal to one billionth of a meter.

Answer 3

its different compared to America and the rest of the world, but I use the metric system. For small distances, i would use meters and centimeters, even millimeters if it was to be precise :)