The key here is that the young man lives in a city and that his life apparently is without social contact. The best choice is therefore “urban . . . reclusive.” “Urban” is rather familiar, deriving from Latin for city. “Reclusive” means living outside of regular society in isolation. It is ultimately derived from the Latin claudere, which means “to close up.” Forms of claudere (and related words) change the “d” to an “s.” (There are other changes internally as well). This leads to many derived words, such as “seclusion,” “occlusion,” “include,” and “inclusion.”

Probably the best way to begin eliminating answers to this question is to note the parallel between the second blank and “lust-filled.” The best match for this would be “carnal,” which implies a tie to “fleshy” or “sensuous” matters.

It is derived from the Latin carnis, meaning meat or flesh. (A related word is “carnivore”—one who eats flesh or meat). The term “intellectual” fits well enough into the first blank, capturing the opposition implied by the sentence structure.

The sentence hints at the use of “light” imagery in the introductory prepositional phrase. While the other options might fit, given this implied light imagery. “Lucent” and “tenebrous” fit this well. “Lucent” means giving off light and is derived from the Latin lux which often is found in related forms containing “luc-,” such as “translucent” and the name “Lucifer,” which means “light-bearer.”

“Tenebrous” is perhaps more unknown and means “dark.” It is derived from Latin words that are close in meaning to this and is reflected in the Christian ceremonies of “Tenebrae” celebrated during Holy Week before Easter, because these celebrations are traditionally tied to the old monastic nightly vigils and morning prayer, much of which would have been prayed in the dark (particularly the vigils).

The easier blank to discern is the second. Since the household was “unstable,” all we can say is that the parents were either “inconsistent” or perhaps “rash.” The other options are not necessarily implied by the context; however, “gregarious” means sociable, which doesn’t make sense in this context. “Submissive” is much better, for it means ready to conform to authority—something that Thomas would not be ready to do, given the details of the rest of the sentence.

Since the authors fear retribution, it is quite likely that they are doing something that is contrary to the wishes of the government; therefore, they could be called “seditious,” which means to work to encourage rebellious activity against authorities. If such persons fear retribution, it makes sense that they would write in a secretive manner. To write “pseudonymously” is to do so under a false (pseudo) name. Although it takes a bit of thinking the “-nym-” can be seen in its relationship to “name.” The prefix “pseudo-” means either “false” or (less strongly) “resembling.” 

The implication of the sentence is that John remained greedy after the lottery, feeling the need to accumulate money, although he did not need to do so. Such a person is called “rapacious,” a word related to the English word “rapt,” which means “having one’s attention utterly taken. The sense of “taken” (or, more distantly, “grabbing”) comes from the Latin base shared between “rapt” and “rapacious.” Someone who is rapacious is one who is constantly “grabbing” after more money or physical goods. A lavish lifestyle is one that is very luxurious. It is derived from the Latin word that gives us “lavatory,” originally meaning “wash room.” Someone who lives a lavish lifestyle is—so to speak—showered with goods.

It can be assumed that the class being discussed in the sentence involves a lot of work based on the start of the sentence, so "demanding" and "rigorous" are the options which make the most sense as choices for the first blank. "Beneficial" means easy and "stringent" means strict, though, so "rigorous . . . stringent" is the correct answer.

"Diminutive" means small in physical stature, while "formidable" means daunting and menacing. Were a small fighter to be a fear-inspiring challenge for a much larger opponent, it would be surprising.

"Incurred" means receive something bad, like a penalty, while "expedient" means benefitting oneself but done out of self-interest. The president brought upon himself the media's criticism for having supported popular legislation in the service of himself.

"Unpredictable" means difficult to foretell or foresee, while "frenetic" means hectic or frantic. It is very reasonable to conclude that a young nephew running at a hectic pace would have a bedtime which is difficult to anticipate, dependent upon his pace subsiding.