The important thing to note in this sentence is that, in his experiment at least, the physicist is unconcerned with the question of the soul’s immortality. The question could be said to be “outside” of his concerns or irrelevant for his considerations. When something is called “extraneous” it is being described as being thus unrelated. The word comes from the Latin for “external” or “foreign.”

Because the customers considered themselves superior, they were most likely arrogant while talking down to me, making them "haughty."

The key word in this sentence is “settling.”  The opening phrase of the sentence stands in contrast to the second clause, and the missing word needs to be the opposite of “settling.”  Only “peripatetic” is an antonym of “settling.”

The key expression here is “insignificant matters.” Therefore, she found John’s critiques to be rather small or insignificant. The best word to describe such things would be “petty,” which means “small” or “trivial.” It is related to the French “petit,” meaning small, and which is often used in English in the same sense.

The idea here is that Caesar never wasted words, so that should mean his dispatches were short. So, we need to pick out an answer choice that means something like short. "Effusive" is the opposite of short; it means overflowing, unreserved, and exuberant.  "Dreary" means boring or uninteresting—it doesn't fit with our expectation of being short.  Neither does "noble," which means upstanding or righteous, nor does "bellicose," which means warlike. The best answer choice is "laconic," which means terse, concise, or using few words.

The best word here is “auspicious,” thought “felicitous” is a very tempting trap word. The latter indicates that something is pleasing or very appropriate for the given circumstances. When something is “auspicious” it is not merely a “happy chance” but moreover indicates (or at least forecasts) future success, something for which Zachary was hoping, as indicated by the interpretation of these signs as hopefully indicating “a positive turn of events.” The word “auspice” literally means a token of prophecy, coming from the Latin word for one who looks at birds to discover the will of the gods. When one says that something was “done under the auspices of X,” he or she means that X supported the given undertaking.

When something fluctuates, its changes in an irregular manner, making it hard to predict that which is fluctuating. That this is the case in our sentence is hinted by the fact that the “volatility was too great” for any kind of forecasting. The word is derived from the Latin verb for “to flow,” and has related English words like “flux” and “influx” as well as “influence” and “fluid.”

The implication in this sentence is that the house was in more disrepair than even many other deteriorating houses in town. The best word to match this sense is “dilapidated,” which means “falling apart due to age or lack of care.” It is derived from the prefix “di-” meaning “apart or down from” and the Latin word for stone, “lapis.” The stone lapis lazuli is so named because it is the stone (lapis) from the place in Persia (now Iran) that was Latinized as Lazulus.

The sense of the sentence is that Luca had many formidable difficulties in his life. If something is particularly difficult in this manner, it is called “redoubtable.” The word does not mean “to doubt again.” Instead, the “re-” prefix here is an intensifier, meaning that the word literally means something like “really doubtable” (because it is so difficult).

The key is that these persons often perform actions with both hands, which is precisely what being “ambidextrous” means. Literally, it means, both (are) right or both hands are as good as right hands.