yes because its kind of like a seesaw if theres too much on one side its unbalance there has to be the same amount of atoms on each side
that seems very false but I believe its the second one
STP stands for standard temperature and pressure. Standard pressure is equivalent to 1 atm, and standard temperature is equivalent to 273.15 K. Therefore, your answer is A. the temperature is 273.15 kelvin.
Hope this helps!
