Si need ! i need the correct answer, thanx! apex

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Which suspect most likely committed the robbery and how do you know