The line that shows the value of the match its the second one "…it was a long, long time before they learned how to kindle one easily". The match allows humankind to handle fire easily.
The sentence that uses the word them as an indirect object would be Leo sent them a postcard from NASA.
Hope this helps and good luck with whatever it is you're doing!
Answer:
the sentence is an object of a preposition. is that what you're trying to know?
its broadest sense, is a rhetorical device, literary technique, or event in which what appears, on the surface, to be the case, differs radically from what is actually the case.