Meaning: 'Triggered' means to cause something to happen or to set off an event, in this case, the mud volcano.

Wrong options:

• created: The word 'created' implies making something new, which does not accurately convey the idea of causing an existing phenomenon (the mud volcano) to occur; it lacks the nuance of causation implied in the context.
• motivated: 'Motivated' suggests providing a reason or incentive for an action, which does not fit the context of causing a geological event; it does not convey the direct causative effect needed here.
• asked: 'Asked' means to request information or action, which is irrelevant in this context as it does not relate to the causation of the mud volcano.

Correct answer: upwelling

Explanation: The term 'upwelling' is contextually appropriate as it refers to the movement of water from the depths of the earth to the surface, which aligns with the geological processes described in the sentence. It fits grammatically as a noun that describes the phenomenon resulting from the drilling.

Meaning: 'Upwelling' refers to the process where water rises from deeper layers to the surface, often bringing nutrients and, in this case, mud.

Wrong options:

• downwelling: The term 'downwelling' refers to the movement of water downwards, which contradicts the context of the mud volcano where material is rising to the surface.
• downside: 'Downside' refers to a disadvantage or negative aspect, which does not fit the geological context of the sentence; it lacks the necessary scientific meaning.
• inside: 'Inside' is a preposition that indicates location within something, which does not apply to the geological process being described.

Correct answer: allowing

Explanation: The word 'allowing' serves as a gerund that indicates permission or enabling, fitting grammatically and contextually as it describes the action that follows the drilling. It connects the drilling to the result of hot water being released.

Meaning: 'Allowing' means to make something possible or to permit something to happen, in this case, the release of hot water.

Wrong options:

• serving: The term 'serving' implies providing or presenting something, which does not fit the context of enabling a geological process; it lacks the causative meaning needed here.
• healing: 'Healing' refers to the process of becoming healthy again, which is irrelevant in this context as it does not relate to the geological processes described.
• noting: 'Noting' means to observe or mention something, which does not fit the context of describing a process that occurs as a result of the drilling.

Correct answer: escape

Explanation: The verb 'escape' fits grammatically as it describes the action of the hot, high-pressure water moving out of the well. It aligns with the context of the sentence, which discusses the release of water due to the drilling.

Meaning: 'Escape' means to break free from confinement or to get away, in this case, referring to the hot water moving to the surface.

Wrong options:

• extract: The term 'extract' implies removal or taking out, which does not accurately describe the natural movement of water in this context; it suggests a more deliberate action than what is occurring.
• explode: 'Explode' suggests a violent burst, which does not accurately represent the process of water moving to the surface; it implies a sudden and destructive action that is not fitting here.
• hide: 'Hide' means to conceal or keep something out of sight, which is the opposite of what is happening in the context of the water moving to the surface.

Correct answer: carried

Explanation: The word 'carried' is the past participle form of the verb that indicates the action of transporting or moving something from one place to another. It fits grammatically and contextually as it describes how the mud was moved to the surface by the water.

Meaning: 'Carried' means to transport or convey something, in this case, the mud being moved to the surface by the water.

Wrong options:

• leaved: The term 'leaved' is not a correct form in this context; the correct past participle is 'left,' and it does not convey the action of moving mud to the surface.
• brought: 'Brought' implies a more active role in the transportation, which does not fit the passive context of the mud being moved by the water; it suggests agency that is not present here.
• narrowed: 'Narrowed' means to make something smaller or more limited, which is irrelevant in this context as it does not relate to the movement of mud.