What do you mean by levels of professions

When a neutrally charged atom loses an electron to another atom, the result is the creation of a. two charged atoms. b. two negatively charged atoms. c. two positively charged atoms. d. two neutrally charged atoms.

Contrast the force of gravity between these pairs of objects: 1-kg mass and a 2-kg mass that are 1 m apart; a 1-kg mass and a 2-kg mass that are 2 m apart; and two 2=kg masses that are 1 m apart. i dont understand.

Which system of units is used by only a small number of countries in the world, including the u.s.