Answer:
It means "importance".
Explanation:
When the text says "To add to the significance of their mission" the text is referring to the addition of importance that the female walk in space will receive, since it will be held in the month of women, as it shows that women have reached places never imagined.
We can reach this conclusion, because the word "significance" refers to something very important, full of meaning and importance.
Vending machines, because each is just a word telling you that both were empty. Vending machines is what the whole sentence is based on.
The correct answer is Ferraro and Newman.
However, you should put the two names behind commas to make it an appositive since it's the key ingredient to making an appositive phrase. Astronomers, Ferraro and Newman, study the speed of stars circling the galactic center of the galaxy. It is an appositive because it describes the astronomers more but is not necessary and could be removed without affecting the truth value of the sentence.
