To “foster” something is to encourage and nurture its development. Since Nathan’s talent is “latent,” it will need to be developed. The sense of the sentence focuses more upon the fostering than on the increase itself, as is indicated by the focus on “positive reinforcement.”

If one "stipulates" something, they clearly demand a set of conditions for an agreement. Often in arguments, one will provide a “stipulative” definition, which is one that is set to have a specific meaning in order to make the argument clearer and more direct (without the nuances of potentially non-stipulated definitions). 

They key word to note is “deadened.” This helps us to avoid “brightened” (and even more so the much weaker “altered”). The weather brought the spirits of the citizens “back to life” from their deadened state; therefore, it “vivified” them.

This word comes from the Latin vivere, meaning “to live.” One can think of many related English words, for instance: survive, vivacious, revive.

The key here is the fact that the workers do the same procedures repetitively. Hence, the best choice is “iterate.”  This word is derived from Latin roots that mean again or to repeat. 

Since the two processes are parallel and “precisely related,” they have to run with exactly the same timing; therefore, while many of the options are tempting, “synchronized” is the best.

This is derived from two familiar Greek words. “Syn” means together or with. It has many English derivatives like “synoptic”—seeing (=optic) together or in the same manner—and symphony. (The latter has also –phony, which comes from the Greek for “sound” and is found in words like “cacophony” and “telephone”). The “-chronized” portion of our word comes from the Greek for “time” and is reflected in words like “chronology” and “chronometer.”

The key meaning for our term is that the young man had finished giving a shine to the instrument. Hence, he had burnished it by thus polishing it.

The key thing to note is that the insurgents not only overthrew the government but that they also replaced those in power. This means that they “usurped” it, a word that implies the taking over of a position or institution by force (not merely removing it from power, regardless of the new state after the overthrow). The word is distantly related to the base of many words regarding “use,” such as “utilize” and “peruse.”

The implication of the sentence is that Oswald would retain the alliance so long as the neighboring realm continued its deliveries. Such an alliance has conditions set for its continuance. Hence, one can call it “conditional” or (here) “conditioned” (e.g. if they continue deliveries, then he will remain an ally).  

The three companies needed to work together, and while this might seem to be an alliance or agreement, it is best described as a case of “collaboration.” The word is derived from Latin roots meaning to work. Related words would be “labor,” “laborious,” and “elaborate.”

The “col-” is derived from the Latin preposition “cum,” which becomes “col-” for phonetic reasons. The preposition means “with,” so in this sentence, “collaborate” means to work with or to work together.

We tend to think of the word “adulterate” as though it were directly linked to “adultery.”  While the latter does imply impurity, this usage is secondary to the sense of making impure, which is the primary meaning of the word’s Latin root; therefore, to “adulterate” is to make impure, which is the case with what Vernon is doing to the steel.