Matter can undergo chemical reactions and nuclear reactions. Which property is conserved in chemical reactions but not in nuclear reactions?

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.