“Demand” is a word that can be used as a noun or a verb, but because all of the potential answer choices can be used as verbs, we will need to consider “demand” as a verb. When used as a verb, “demand” means “say in a forceful way,” so we need to pick out an answer choice that means something like “say forcefully.” That means that “reject” cannot be the correct answer, because “reject” can mean “dismiss” or “refuse,” two meanings very different from that of “demand.” “Insist,” however, is a verb that means “not accepting refusal,” and because “insist” is the answer choice closest in meaning to “demand,” “insist” is the correct answer.

"Wager" is a word that when used as a noun, means "an agreement in which people try to guess what will happen and the person who guesses wrong has to give something (such as money) to the person who guesses right," and when used as a verb, means "to risk losing something (such as money) if your guess about what will happen is wrong." So, we need to pick out an answer choice that is either a noun that means something like "an agreement in which people try to guess what will happen and something (such as money) is at stake," or a verb that means "to enter into such an agreement." "Bet" is a word that when used as a noun means "an act of risking a sum of money on the outcome of a future event," and when used as a verb means "risk something, usually a sum of money, against someone else's on the basis of the outcome of a future event, such as the result of a race or game." Because "bet" is the answer choice closest in meaning to "wager," "bet" is the correct answer.

"Ditch" is a word that when used as a noun, means "a narrow channel dug in the ground, typically used for drainage alongside a road or the edge of a field." When used as a verb, "ditch" can mean "provide with ditches," or, informally, "get rid of; give up." Because all of the answer choices are verbs, we will need to consider "ditch" as a verb pick out an answer choice that means something like "provide with ditches" or "get rid of." "Follow," then, cannot be the correct answer, because if one is following someone, they are not abandoning them. "Desert," however, is a word that when used as a verb means "abandon (a person, cause, or organization) in a way considered disloyal or treacherous," and because "desert" is the answer choice closest in meaning to "ditch," "desert" is the correct answer.

As a noun, "blend" refers to a combination or mixture; as a verb, it means mix substances together. In any case, "mixture" is the best choice here. "Separation," or the act of moving parts away from each other, is the opposite of the correct synonym. "Progress" and "activity" are unrelated.

"Estimate" is a word that can be used as a noun or a verb, but because all of the potential answer choices are verbs, we will need to consider it as a verb. When used as a verb, "estimate" means "roughly calculate or judge the value, number, quantity, or extent of," so we need to pick out a verb that means something like "roughly calculate." So, "pinpoint" cannot be the correct answer, because when used as a verb, "pinpoint" means "find or locate exactly," which is not close in meaning to "roughly calculate." "Approximate," however, is a word that when used as a verb, means either "come close or be similar to something in quality, nature, or quantity" or "estimate or calculate (a quantity) fairly accurately." Because "approximate" is the answer choice closest in meaning to "estimate," "approximate" is the correct answer.

While "moderate" can be taken to mean an adjective meaning middling, average, or intermediate, it can also be used as a verb meaning diminish or make less. If you moderate your anger, for instance, you calm down and become less angry. Based on this definition, the correct answer is "lessen."

The word “average” is often used as an adjective meaning of middling quality in a given group. However, the word can also be used as a noun meaning mathematical mean. The correct answer to this question requires you to recognize this secondary definition, as "fantastic" is far from meaning of middling quality and can't be the correct answer.

The word "contest" has multiple meanings, one of which is a clash between two entities. (This one is pronounced "CON-test.") It can also be used as a verb ("con-TEST") that means to dispute or question a decision and ask that it be reconsidered. "Question" is thus the correct answer.

"Function" can be used as either a noun or a verb. When used as a noun, "function" means purpose; when used as a verb, "function" means work properly. So, "work" is the correct answer. “Demand” means forcefully ask or say something has to be done.

Do not confuse the word "assault" with "insult." A number of the wrong options are meant to tempt you to make this mistake. Do not fall for it! The word "assault" means to attack physically, or merely to attack. An army can assault a city, and a person can assault another person. In both cases, we are referring to some kind of physical attack. Sometimes, the word is used in a secondary sense to describe any kind of attack, like a "verbal assault." Still, the general meaning that is retained is that of attacking. Therefore, the best option among those provided is "attack."