C. Spacecraft are built to be airtight.
Answer:
C. Lithium is most easily oxidized of the metals listed on the activity series and therefore it will most easily give electrons to metal cations
Explanation:
"Lithium" is a type of alkali metal that has a "single valence electron." Since it is a reactive element, it easily gives up an electron when it is combined with other elements. Such giving up of electron is meant to create compounds or bonds.
Among the common metals listed, "lithium" is the most easily oxidized. This means that it donates its electrons immediately. Such combination makes it exist as a<em> "cation"</em> or <em>"positively-charged."</em>
So, this explains the answer.