A.I. Explanation:

Correct answer: swear in

Explanation: The phrase 'swear in' is used here to indicate a strong commitment or promise made by health enthusiasts regarding their habit of morning exercise. It fits grammatically as it aligns with the subject 'numerous health enthusiasts' and conveys the intended meaning of dedication to this practice.

Meaning: 'Swear in' means to make a solemn promise or commitment, particularly in the context of adopting a habit or routine.

Wrong options:

• call on: This phrase typically means to request someone to speak or to visit someone, which does not fit the context of making a commitment to a habit.
• bring up: This means to introduce a topic or mention something, which is not relevant to the context of committing to a habit.
• turn down: This means to reject or refuse something, which contradicts the idea of embracing a morning exercise routine.

Correct answer: kick start

Explanation: The term 'kick start' is appropriate here as it conveys the idea of initiating or energizing something, specifically your metabolism. It fits grammatically and contextually, as it describes the positive effect of morning exercise on metabolic activity.

Meaning: 'Kick start' means to begin something with energy or enthusiasm, particularly in this context referring to boosting metabolism.

Wrong options:

• boost up: While 'boost' is relevant, 'boost up' is not a standard phrase and does not fit grammatically in this context.
• put off: This means to delay or postpone, which is the opposite of the intended meaning of energizing the metabolism.
• break down: This means to fail or collapse, which does not align with the positive context of enhancing metabolism.

Correct answer: with

Explanation: The preposition 'with' is correctly used here to indicate the association between a morning routine and exercise. It fits grammatically and contextually, as it shows how exercise is integrated into the routine.

Meaning: 'With' indicates association or accompaniment, meaning that exercise is part of the morning routine.

Wrong options:

• of: This preposition indicates possession or belonging, which does not convey the intended relationship between the routine and exercise.
• from: This suggests a source or origin, which is not appropriate in this context of describing a routine that includes exercise.
• on: This preposition typically indicates a position or surface, which does not fit the context of describing a routine.

Correct answer: enhance

Explanation: The verb 'enhance' is suitable here as it means to improve or increase the quality of something, specifically your mood. It fits grammatically and contextually, as it describes the positive impact of morning exercise on emotional well-being.

Meaning: 'Enhance' means to improve or make better, particularly in this context referring to mood improvement through exercise.

Wrong options:

• elevate: While 'elevate' means to raise or lift, it is less commonly used in the context of mood compared to 'enhance.'
• undermine: This means to weaken or damage, which is the opposite of the intended positive effect of exercise on mood.
• diminish: This means to reduce or lessen, which contradicts the idea of improving mood through exercise.