To "conclude" means to end; the second part of the sentence after the semi-colon makes it clear the scientists are ending their work, and should not continue, as they already have clear results. "Futile" in this case means counterproductive or pointless; "sensible" is its opposite.

The first important clue here is the word "formerly," suggesting that there will be a shift in meaning contrasted with the word "now." The last part of the sentence tells us that the lake was changed in a negative way. Only "pristine" and "adulterated" fit the meaning of the sentence.

The sentence contains clues that his girlfriend might not be completely sincere in her career advice. "Long-winded explanations” and “speeches on how she could be better organized” are mentioned. “Didactic” means instructive. It is often used in a negative way, which is fitting for this sentence. To “advert” means to turn the attention to. “Adverted . . . didactic” is the best answer.

“Rudimentary” refers to something being basic or at an early stage of development. “Perfunctory” refers to something done without great care or interest. Neither of these words will work, given the context. Also, note that “extenuate” does not mean to extend, but to make light of or treat as less serious. “Aggrandize” means to make greater. “Exhaustive” means to perform completely. “Aggrandize . . . exhaustive” is the correct answer.

We know that the value of Theo's stocks is dropping ("plummeting") because he's losing thousands of dollars. The fact that he "never lets on the turbulence he feels" indicates that he is "impassive," or stoic.

“Aromatic” is similar to “aroma,” except that it refers exclusively to things that smell good. “Savory” has a similar definition. “Acrid” refers to a sharp, unpleasant smell. “Permeate” means to fill or pass through every part. “Acrid . . . permeating” is the correct answer.

Note that the first part of the sentence presents us with a double shift, indicated by “though” and “anything but.” Thus, both parts of the sentence are more or less equivalent. “Jaded” means to make weary or dull. “Visceral” refers to an intuitive feeling involving base emotions. To “addle” means to confuse. “Visceral . . . addled” is our answer.

The disinterest of the students is the best clue for assessing this situation. Likely, they are staring back at the professor with empty and disengaged stares. These could be called "indolent," indicating a kind of laziness. It would be better to look for something that more directly indicates the lack of interest. The word "passive" works well in this case, as it helps us to imagine the students staring back without really any external reaction on their faces whatsoever. The professor seems to want them merely to talk about anything whatsoever. That means that she would like them to engage her in a conversation on any topic. To be engaged does not only have to deal with getting married! It can merely mean "to be involved with in some way."

“Desecrate” means to defile or mistreat something sacred. This doesn’t work, given the context. “Prevaricate” means to mislead. To “amass” is to gather or collect over time. “Malodorous” is another way of saying that something stinks. “Amassed . . . malodorous” is the correct answer.

“Incite” and “goad” denote encouraging or prompting to action. If the patient's doctor had given him pills to trigger symptoms, then the patient needs to switch physicians. “Ancillary” describes something that aids or provides support. “Alleviate” means to lessen or make something easier. “Ancillary . . . alleviate” is the correct answer.