The atomic mass of an element is defined as the weighted average mass of that element's? (1) most abundant isotope (3) naturally occurring isotopes (4) radioactive isotopes

What would you do if you told the guy you liked that you liked him

If an area has high air pressure and low humidity, what type of weather will it most likely have? plz !

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?