The sentence comments that the "new research" backed up arguments the academic "had been making for thirty years." This means the academic was supported or bolstered by the research, and the correct answer must reflect this fact. "Vindicated," meaning proved right or removed blame, is the best choice among the answers.

The word "although" is a clue that there is some contradiction between the speaker's characterization of the woman's actions and the speaker's contention of the woman's sentimentality. If the woman's actions were self-described as "empathetic," there would be no contradiction. The best choice in this case would be "pragmatic," which means focusing on practical results rather than principles or emotions.

Someone might consider the task of bathing a dog to be "simple," "straightforward," or "rudimentary," all meaning basic. Someone who thinks the task is especially easy also might call it "negligible"; however, these do not make sense contextually, because the dog in question does not like water: this would make the task of bathing him "onerous," meaning burdensome.

"Unobservant," "vapid," and "obtuse" all describe a mind that is not astute, and this is not what doctors would want to help their patients achieve. "Impermeable," meaning not susceptible, could work, but if the mind in question were impermeable, then there would be no question of the person ever having dementia. "Shrewd," meaning sharp, is thus the best choice.

Among the answers, the most tempting are perhaps "tedious," "astute," and "recondite." There are two potential key phrases in the second sentence: "inexhaustible knowledge" and "arcane details." "Tedious" might apply in the second case, but its claim is rather weak. There is no discussion of the annoyance that comes with tedium. Although inexhaustible knowledge might be astute, such a claim is rather weak as well. The best option is "recondite," which implies that something is little known or obscure.

This sentence is meant to be a trap. The expression "looked intently" nearly rolls off one's tongue, but that does not make for a correct sentence completion. The sentence indicates that John was "wholly indifferent"; therefore, his gaze would have to be little-focused on Suzanne—no matter how exaltant this moment might be; therefore, the only acceptable answer is the one that accords to this indifference: "blankly."

The apposition at the end of the sentence indicates the sense of the missing word. A depressed person might be "disconsolate," but that does not give an absolute fit to the description of being unable to exert energy. Likewise, "lax" might seem tempting—a lax person not finishing a task well—but that is not the same as being unable to exert energy.  The best answer is "enervated," which captures the sense of being without energy.

The best phrase to use to find the answer is "his temper flared." The correct answer, then, will relate in some way to a temper or anger. "Irascible," meaning easily angered and annoyed, is the correct answer.

The two key words in the sentence are "strange" and "peculiar." The correct answer needs to accurately describe what unfamiliar writing will do to high school students. "Befuddled," meaning confused, is the correct answer.

The subject of the sentence is uncomfortable with mental challenges, and that is contrasted by the correct answer choice. "Intellectual" and "philosophical" are able to be eliminated as near synonyms with "mental." "Puny" and "timorous," on the other hand, indicate a cowardice or weakness that does not make sense in the sentence. The correct answer is "brawny," which means having to do with physical strength.