The word "commemorate" means celebrate. "Celebrate" is the best choice because it is part of the definition of "commemorate." Considering the other choices, "recall" means recall information, "comment" means respond to something verbally, and "disdain" means to be disgusted by.

If something or someone is concealed, they are hidden from view or camouflaged.

An illustrative example with the word evict is when someone is evicted from their home.  This means that they are removed.

"Merge" is a verb that means "combine or cause to combine to form a single entity," so we need to pick out an answer choice that means something like "combine." "Split" cannot be the correct answer, then, because "split" means "break or cause to break forcibly into parts, especially into halves or along the grain," making it an antonym, not a synonym, of "merge." "Unite," however, is a verb that means "come or bring together for a common purpose or action," and because "unite" is the answer choice closest in meaning to "merge," "unite" is the correct answer.

"Incarcerate" is a verb that means "imprison or confine," so we need to pick out an answer choice that means something like "imprison." "Release," then, cannot be the correct answer, because "release" means "allow or enable to escape from confinement; set free," making "release" an antonym, not a synonym, of "incarcerate." "Jail," however, when used as a verb, means "put (someone) in jail," and because "jail" is the answer choice closest in meaning to "incarcerate," "jail" is the correct answer.

"Vanish" means to disappear.

"Deplete" means to use up a supply, as in the sentence, "When your food supplies become depleted, you will need to buy more."

"Diminish" is the correct answer because it means to make or become less. Both "deplete" and "diminish" have to do with a quantity becoming smaller.

Incorrect answers:

"Designate" means to appoint to a position, as in the sentence, "The class election was a tie, so the teacher designated a student as the class president."

"Enter" means to go into, as in the sentence, "Make sure your headlights are on when you enter the tunnel."

"Imitate" means to copy or to follow as a model, as in the sentence, "The winner of the talent show imitated a famous singer."

The word "distort" means to twist out of shape. "Change" is the best option because it is the only choice that has to do with changing the shape of something else. Considering the other choices, "insult" means to be rude towards another, "distinguish" means to make different, and "attract" means to draw in. 

The word "circumvent" means avoid. "Avoid" is the best choice, as it is a part of the definition of circumvent. Considering the other choices, "wind" is air in motion, "round" means circular or curved, and "assist" is a verb that means help.

The word "incarcerate" means put in jail or imprison. "Imprison" is the best choice because it is a part of the definition of "incarcerate."