Meaning: 'Surprising' means causing astonishment or wonder, indicating that the truth about comets was not what was commonly expected.

Wrong options:

• Wonders: 'Wonders' is a noun and does not fit grammatically in this context, as the sentence requires an adjective to describe the truth.
• alarm: 'Alarm' implies a sense of fear or concern, which does not align with the context of unveiling a scientific truth about comets.
• validity: 'Validity' refers to the quality of being logically or factually sound, which does not appropriately describe the nature of the truth being discussed.

Correct answer: prevalence

Explanation: The word 'prevalence' fits grammatically as a noun that indicates the commonness or widespread occurrence of parabolic orbits, which is the focus of the sentence. It logically connects to the idea of comets being temporary guests.

Meaning: 'Prevalence' means the state of being widespread or commonly occurring, highlighting how often parabolic orbits are observed among comets.

Wrong options:

• Honorary: 'Honorary' refers to a title or distinction given as an honor, which does not relate to the context of comet orbits.
• baptism: 'Baptism' is a religious ceremony and does not fit the scientific context of discussing comet paths.
• commonly: 'Commonly' is an adverb and does not fit grammatically as a noun in this context, where a noun is needed to describe the state of orbits.

Correct answer: Eventually

Explanation: The word 'Eventually' fits grammatically as an adverb indicating that the action of disappearing occurs after some time. It logically connects to the context of comets' journeys.

Meaning: 'Eventually' means at a later time or after a while, suggesting that the disappearance of comets is not immediate but happens over time.

Wrong options:

• certain: 'Certain' is an adjective that does not fit grammatically in this context, as the sentence requires an adverb to describe the timing of the disappearance.
• meddle: 'Meddle' means to interfere in something that is not one's concern, which does not relate to the context of comets disappearing.
• crews: 'Crews' refers to groups of people working together, which is irrelevant to the context of comet visibility and their paths.

Correct answer: fleeting

Explanation: The word 'fleeting' fits grammatically as an adjective describing the type of glimpse offered by comets. It aligns with the context of their temporary nature.

Meaning: 'Fleeting' means lasting for a very short time, emphasizing the brief visibility of comets.

Wrong options:

• Fondly: 'Fondly' is an adverb that describes a manner of affection, which does not fit grammatically or contextually in describing a glimpse.
• floats: 'Floats' is a verb that does not fit grammatically in this context, where an adjective is needed to describe the glimpse.
• favour: 'Favour' is a noun or verb that does not appropriately describe the nature of the glimpse in this context.

Correct answer: consequence

Explanation: The word 'consequence' fits grammatically as a noun that indicates the result or effect of the unique trajectories of comets. It logically connects to the idea of their brief spectacle.

Meaning: 'Consequence' means a result or effect of an action or condition, highlighting that the beauty of comets is a result of their unique paths.

Wrong options:

• Grudges: 'Grudges' refers to persistent feelings of ill will, which does not relate to the context of comet visibility.
• summarily: 'Summarily' is an adverb that does not fit grammatically as a noun in this context, where a noun is needed to describe the spectacle.
• blessing: 'Blessing' implies a beneficial thing, which does not accurately capture the nature of the spectacle as a result of their trajectories.