What is the definition of a common union?

Ascientist performs an experiment where she measures the mass of a piece of metal, pours acid onto the metal, washes the metal, and then re-measures the mass of the metal. the scientist repeats the experiment several times, each time increasing the amount of acid used. the dependent variable in the experiment is the: initial mass of the metal final mass of the metal amount of acid used washing the metal

Did everyone shared in the economic prosperity of the 1920’s

Which event occurred in 1943 and to make the allied victory possible choose all answers that are correct