15 points, ASASP ASAP PLEASE!

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

The diagrams show objects’ gravitational pull toward each other. which statement describes the relationship between diagram x and y? gravity attracts only larger objects toward one another. gravity attracts larger objects only if they are close to one another. if the masses of the objects increase, then the force between them also increases. if distance between the objects increases, then the amount of force also increases.