"Robust" means strong and sturdy, so "sturdy" is the correct answer. "Fragile" is an antonym of "robust" and "sturdy"; it means weak and easily broken. "Flawed" means having defects or problems. "Humorous" means funny or hilarious. "Illiterate" means not knowing how to read or write, as the negative prefix "il-" means not, and "literate" means knowing how to read and write. This makes sense because the root "lit" means having to do with letters; the root appears in other words like "literature" and "alliterate."

"Grimy" means dirty or filthy, so "filthy" is the correct answer. "Immaculate" is an antonym of "grimy" and "filthy"; it means perfectly clean. "Enormous" means very big in size. "Energetic" means lively or having a lot of energy. "Studious" means spending a lot of time on academic work.

"Tepid" means of a temperature that is mild, verging on cold. So, it is most similar in meaning to "lukewarm," which means of a moderate temperature, and "lukewarm" is the correct answer. For clarification, "stifling" means very hot, "frigid" means very cold, "boring" means not holding one's attention or interest, and "conclusive" means definitive.

Someone who is parched is very thirsty, so "thirsty" is the correct answer. For clarification, "hungry" means needing food, "tired" means lacking energy or needing sleep, "sad" means unhappy and "happy" means glad or cheerful.

Someone who is "nimble" is highly flexible and agile, so "flexible," which means able to bend, is the correct answer. For clarification, "rudimentary" and "elementary" are synonyms that both mean basic or simple, "complex" is an antonym of "rudimentary" and "elementary" that means complicated, and "frigid" means very cold.

"Pristine" means clean or unused, so "clean" is the correct answer. None of the other answer choices are close in meaning to "pristine": "unyielding" contains the negative prefix "un-," which means not, so you might be able to infer that it means not yielding, or in other words, stiff or inflexible; "famous" means well-known; "intricate" means complex or complicated; and "unconcerned" means not concerned or not interested, which you again might be able to infer from the presence of the prefix "un-."

"Stiff" means "rigid" or difficult to bend. "Flexible" is an antonym of "rigid"; it means easily changeable or bent. "Delicious" means very tasty. "Boring" means dull or uninteresting. "Selfless" means unselfish or concerned more with others than with oneself.

Someone who is "emaciated" is very thin, to the point of being unhealthy, so "very thin" is the correct answer. "Emaciated" is an antonym of "corpulent," "portly" and "fat."

"Immaculate" means perfectly clean or perfectly behaved, so "spotless," and adjective that also means perfectly clean, is the correct answer. For clarification, "imperfect" means not perfect, as you might guess from the word's use of the negative prefix "im-." It is an antonym of "immaculate." For further clarification, "frank" means honest, "zealous" means passionate, and "vociferous" means vocal or loud.

If someone or something is “emaciated” they are very thin and bony. For example, one could write, "After the famine, the farm animals were “emaciated.” “Gaunt” means thin and bony and usually pale. If you say, "His face looked gaunt," you mean it was thin, pale, and bony. To further help you ,“fibrous” means stringy or made of fibres, so chewy meat is “fibrous.” “Sensitive” means easily offended or sympathetic to other people’s feelings.