The word "impersonal" is made up of two parts: "im" and "personal." The "im-" prefix is a form of the "i-" prefix that means not. To be "impersonal" is to be "non-personal." Now, that seems a bit strange at first sight. However, to be "non-personal" means that something does not show the kind of individual characteristics that a person would show. For instance, a "personal" letter is one that is written directly for someone else, often containing things that show that the letter writer knows the person to whom he or she is writing. However, an "impersonal" letter is one that is written without really paying attention to its receiver. We receive these kinds of "impersonal" letters in the mail when we get something from a company telling us about new services. (Many other examples could be provided, of course!)

The best option among those provided is "formal," which means following a given way of acting, or in other words, following a given form of acting. This implies that someone or something is not "particular" (as would be something "personal"). Instead, it follows a given "form" that can be applied to anything or anyone whatsoever.

Indigenous is defined as innate and inherent, which makes it natural. 

In terms of something that is remote such as a remote island, it means that it is distant.

Something that is "systematic" occurs as the result of a system or plan that has been put into play. Something that is "systematic" is thus "efficient" becauase it has been planned out to be as useful and direct as possible in achieving its results.

"Vacant” means empty or unoccupied, so "empty" is the correct answer. As for the other answer choices, “meaningful” means important and significant; “insignificant” means not important; “quirky” means unconventional.

"Maritime" is an adjective that means "connected with the sea, especially in relation to seafaring commercial or military activity," "living or found in or near the sea," "bordering on the sea," or "denoting a climate that is moist and temperate owing to the influence of the sea." While "wet" might look like the correct answer because both "wet" and "maritime" can be associated with water, "wet" does not mean the same thing as "maritime" and cannot be the correct answer. "Nautical," however, means "of or concerning sailors or navigation; maritime," and because it is the answer choice closest in meaning to "maritime," "nautical" is the correct answer.

The adjective "prior" indicates that something comes before another thing. For instance, if you already have some knowledge of frog anatomy when your class begins to cover this subject, your biology teacher could say that you have "prior knowledge." The word "prior" is opposed to the word "posterior," which means coming after. A "prior commitment" is a commitment or meeting that you have scheduled at an earlier point in time. While things like "prior knowledge" might be simple in comparison with later developments of that knowledge, the best option among the answers is the one that draws attention to the general notion of being "before." Hence, "preceding" is the best option, for "preceding" means coming before.

If something is "fitting" it is appropriate, just right, perfect for the occasion. To provide further help, "inappropriate" means not fitting; "energetic" means full of energy; "unremarkable" means not remarkable, not interesting; "untrustworthy" means not trustworthy, not deserving of trust. 

When something is "remote," it is not close. Now, for this reason, sometimes things that are very isolated are called remote. For instance, we can refer to a "remote desert island." This refers to an island that is very far away from any civilization (or any land whatsoever). The words "rural" and "farmed" do not necessarily imply being remote. They may be, but that is not necessarily the case. The best option provided is "distant."  A "remote control" for the TV is given this name because it allows you to control it from a distance.

"Feeble" is an adjective that can mean "lacking physical strength, especially as a result of age or illness," "faint" when referring to a sound, "lacking strength of character," or "failing to convince or impress." So, we need to pick out an answer choice that means something like "lacking strength." That means that "strong" can't be the correct answer, because "strong" is an antonym of a word that means "lacking strength." "Weak," however, means "lacking the power to perform physically demanding tasks; lacking physical strength and energy." Because "weak" is the answer choice closest in meaning to "feeble," it is the correct answer.