History question help

Which is likely the most serious problem associated with an epidemic? 1. there are sometimes no cures to the diseases that spread. 2. people often die from the diseases that spread. 3. there are usually no ways to prevent people from getting ill. 4. people often don’t know they have a disease.

Brainliestttme : ) -what reforms were made in communist china?

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