Definition: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
Input: Walton Simons:  You ca n't begin synthesizing the vaccine without a universal constructor , and do n't think we 're going to just leave _ one _ lying around . Not after you blew up the one in Hong Kong .
JC Denton: I was never properly trained in its operation .

constructor