Answer:
The correct answer is nanoscale.
Step-by-step explanation:
A branch of nanotechnology that utilizes standard size apparatuses to produce basic compositions and tools with dimensions on the range of few nanometers or even less, that is, 1 nm is equivalent to a billionth of a meter, that is, it operates at an atomic level. It has an application in sanitation, water purification, medicine, agriculture, and others.