There is a theory that gravity could pull galaxies back together, causing a reverse big bang.
which observation makes this theory less likely than the idea that the universe may continue to expand?
a.) background radiation is present.
b.) galaxies exist outside of the milky way.
c.) the expansion of the universe is accelerating.
d.) gas giants form farther from the sun, where temperatures are cooler.

One way in which the useful metal copper is produced is by dissolving the mineral azurite, which contains copper(ii) carbonate, in concentrated sulfuric acid. the sulfuric acid reacts with the copper(ii) carbonate to produce a blue solution of copper(ii) sulfate. scrap iron is then added to this solution, and pure copper metal precipitates out because of the following chemical reaction: (s) (aq) (s) (aq) suppose an industrial quality-control chemist analyzes a sample from a copper processing plant in the following way. he adds powdered iron to a copper(ii) sulfate sample from the plant until no more copper will precipitate. he then washes, dries, and weighs the precipitate, and finds that it has a mass of .