The prefix "mis-" means not, wrong, or bad, and the word “mistake” means something done wrong, or an "error." To provide further help, a “solution” is an idea about how to fix a problem; a "detraction" is something that takes away from a positive state of something else; a "mystery" is a situation in which something is unknown or a book, movie, or play involving the solving of a crime that is difficult to understand; and a "detail" is a specific aspect of something.

“Defunct” means no longer working or in existence. As such, it is most similar to the word “unusable," which means not able to be used. In this word, the negative prefix "un-" means not and makes "unusable" mean the opposite of "usable." To provide further help, “penniless” means completely poor and without possessions; “tiresome” means boring; “passive” means not fighting, peaceful, or not aggressive; and “brief" means lasting for a short time or concise. 

"Extraterrestrial" means alien when used as an adjective, and an "extraterrestrial" is is an alien. So, "alien" is the correct answer. To help you understand the formation of words, consider that "terrestrial" means from the earth and in this context, the prefix "extra-" means something other than. So an extraterrestrial is something from somewhere other than the earth. To help you further, "extraordinary" means something other than ordinary, "ordinary" means normal, a "foreigner" is someone from another country, and a "citizen" is a member of a nation.

If you are “hypersensitive” you are overly sensitive to things. For example, you may easily have your feelings hurt. The prefix "hyper-" usually means overly.

To “surpass” is to go beyond or to become better than someone or something. “Exceed” also means to go beyond the limit of something or to become better than someone or something. Look for prefixes like "sur-" and "ex-" where "sur-" can mean above and "ex-" can mean out of. To further help you, “recede” means to go back, so you can say waves “recede” on the shore.

The prefix "un-" is a negation prefix and usually means not, so the word “unacceptable” means not acceptable. Of the answer choices, this is closest in meaning to “intolerable,” which means not tolerable. The prefix "in-" is used very much like the prefix "un-." To provide further help, “unmitigated” means not mitigated, pure; “domesticity” is life inside the home; “meticulous” means careful, paying great attention to detail; “incomprehensible” means not able to be understood. 

The prefix "under-" means beneath or below, so the word “underage” means below age, immature. To provide further help, a “novice” is a beginner and an “expert” is someone who has been doing something for a long time and is very good at it; a “vendor” is someone who sells things; a “genius” is someone who is very smart. 

“Dismount” means to get down. It is commonly used when speaking about “dismounting" from horses, as in to get off your mount. The prefix "dis-" is a negation prefix and the suffix "-mount" refers to something you sit on.

The prefix "semi-" usually means half, so we can assume that a “semicircle” is half a circle. To provide further help, a three-dimensional circle is called a “sphere;” “parallel” means running alongside, having the same slope; “slope” means slanted ground; “gradient” means slope. In addition to being terms we use in English, these are also all mathematical terms. 

The prefix "under-" means below or beneath, so the word “underdeveloped” means not grown enough, not developed enough. To provide further help, “developed” means grown; “beneath” means under.