The atomic mass of an element is the weighted average of the masses of… 1) its two most abundant isotopes
2) its two least abundant isotopes
3) all of its naturally occurring isotopes
4) all of its radioactive isotopes

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.