C because it is and I know
The correct answer is option C, that is, it is reduced.
In reduction and oxidation reactions, reduction refers to the loss of an oxygen atom from a molecule or the gaining of one or more electrons. A reduction reaction is observed from the perspective of the molecule being reduced, as when one molecule gets reduced, another one gets oxidized. The complete reaction is called a redox reaction.
In the given case, iron gains electrons mean that it is reduced.
The answer is temperature (may be wrong)
hot air rises up in the balloon and lifts the balloon up
Since there is 9.47 x 1021 atoms of copper in 1 gram, and 8.96 grams/cc is the density of copper, then 9.47 x 8.96 =84.85 x 1021 atoms of copper in the one cubic centimeter of copper.