Why did congress created the law that allowed 18 year olds to vote?

Why did stalin want control of eastern europe after ww2?

How can we stop u.s. military drone strikes from hurting innocent people

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