Stone (US): While the stone is not commonly used in the United States, it is equivalent to 14 pounds (approximately 6.35 kilograms). In some contexts, people may refer to their weight in stones.
A nanogram (ng) is a metric unit of mass in the International System of Units (SI). It represents one billionth of a gram or 10^-9 grams. The metric system is a decimal-based system of measurement used worldwide, and it provides a convenient way to express very small quantities of mass.
To put the size of a nanogram into perspective:
Nanograms are commonly used in various scientific and analytical fields where precise measurements of tiny quantities of substances or particles are necessary. Some examples of their usage include: