Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas. which group of statements best describe all of the materials he is using in the investigation?

The answer here is B they are each made of matter. some are compounds, and some are elements they all contain Atoms this is because Silver and Oxygen are elements while Carbon Dioxide and Water are compounds. Although you do not have the choices down, I have come across this question before.