Meaning: 'Preservative' refers to a substance that is added to food to prevent it from spoiling or to maintain its freshness.

Wrong options:

• preserving: This is a gerund form and does not function as a noun in this context, making it grammatically incorrect here.
• preserve: This is a verb and does not fit the noun requirement of the blank, as it does not describe a substance.
• preserved: This is the past participle form and does not serve as a noun, thus failing to fit the grammatical structure needed.

Correct answer: In addition

Explanation: The phrase 'In addition' serves as a discourse marker that introduces an additional point, fitting well with the context of adding information about vinegar's health benefits. It maintains the formal tone of the text.

Meaning: 'In addition' means 'also' or 'furthermore,' indicating that what follows is another important point related to the previous statement.

Wrong options:

• Although: This introduces a contrast rather than an addition, making it contextually inappropriate here.
• Firstly: This implies a sequence of points, which does not fit as the sentence is not listing items in order.
• Another: This is less formal and does not serve as a proper transition phrase in this context.

Correct answer: in

Explanation: The preposition 'in' correctly indicates the context of fighting cancer, aligning with standard English usage for describing effectiveness in a particular area or activity.

Meaning: 'In' is used to indicate a location or context, here referring to the action of fighting cancer.

Wrong options:

• on: This preposition does not fit the context of effectiveness in fighting cancer, as it typically indicates a surface or topic rather than a context of action.
• of: This preposition does not convey the intended meaning of effectiveness in this context, as it suggests possession rather than involvement.
• about: This preposition implies a general discussion rather than a specific action, making it unsuitable here.

Correct answer: has been shown

Explanation: The phrase 'has been shown' is the correct present perfect passive form, indicating that the action of showing has occurred at an unspecified time in the past and is relevant to the present context.

Meaning: 'Has been shown' means that evidence or results have been presented or demonstrated regarding the effectiveness of the vinegar.

Wrong options:

• has been show: This is grammatically incorrect as 'show' should be in the past participle form 'shown' to match the present perfect tense.
• have been shown: This is incorrect because the subject 'one Japanese rice vinegar' is singular, requiring 'has' instead of 'have.'
• has be show: This is incorrect due to the missing past participle form 'shown,' making it grammatically invalid.

Correct answer: put on

Explanation: The phrase 'put on' is the correct phrasal verb that means to gain weight, fitting the context of the sentence about the effects of cranberry juice on weight.

Meaning: 'Put on' means to gain or increase in weight, which is relevant to the context of the experiment described.

Wrong options:

• put off: This means to delay or postpone, which does not relate to weight gain and is contextually inappropriate.
• carried off: This phrase typically means to take something away, which does not fit the context of weight gain.
• got on: This is an informal phrase that does not convey the specific action of gaining weight, making it unsuitable here.

Correct answer: powers

Explanation: The noun 'powers' fits grammatically as it refers to the abilities or capacities of the brain, aligning with the context of discussing improvements in reasoning and memory.

Meaning: 'Powers' refers to the abilities or faculties of the brain, particularly in terms of reasoning and memory enhancement.

Wrong options:

• influences: This is a verb and does not fit the noun requirement of the blank, failing to describe the brain's capabilities.
• thoughts: This is a plural noun that does not encapsulate the broader concept of brain abilities as effectively as 'powers.'
• dreams: This refers to a specific type of thought during sleep and does not relate to reasoning or memory in the context provided.