Define electrons and figure

The electron is the universe's fundamental unit of negative charge. ... It is believed to be truly fundamental, because it cannot be split into smaller particles, and it has no detectable structure. Its symbol is usually e- or β-.

Explanation:

The electron is the universe's fundamental unit of negative charge. ... It is believed to be truly fundamental, because it cannot be split into smaller particles, and it has no detectable structure. Its symbol is usually e- or Significant figures are the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value. We start counting significant figures at the first non-zero digit.

Explanation:

measure their densities same density, same sub