Meaning: 'Force' refers to physical power or strength, especially when used to compel or coerce someone, which is relevant in the context of international relations and conflict resolution.

Wrong options:

• might: Might is a modal verb indicating possibility, which does not fit the context of a noun needed here.
• vigor: Vigor refers to physical strength and good health, but it does not convey the idea of coercion or violence in this context.
• control: Control implies power over something but does not specifically denote the use of violence or force, making it less suitable.

Correct answer: over

Explanation: The preposition 'over' is used to indicate the subject of a dispute, making it the correct choice as it shows the relationship between the countries and the issue at hand.

Meaning: 'Over' in this context means regarding or concerning, indicating the subject of the dispute is the oil-rich region.

Wrong options:

• on: On typically indicates a surface or a topic but does not convey the same relational meaning as 'over' in disputes.
• in: In suggests being inside something, which does not fit the context of a dispute between two nations.
• at: At indicates a specific location or point, which is not appropriate for discussing the subject of a dispute.

Correct answer: reaffirmed

Explanation: The verb 'reaffirmed' is used correctly here as it means to state again or confirm, which fits the context of a leader expressing commitment to peace.

Meaning: 'Reaffirmed' means to confirm or assert again, indicating a strong commitment to peace.

Wrong options:

• verified: Verified means to confirm the truth or accuracy of something, which does not convey the same sense of commitment as 'reaffirmed.'
• reinforced: Reinforced suggests strengthening something already established, but it does not imply the act of confirming a commitment as strongly as 'reaffirmed.'
• acknowledged: Acknowledged means to recognize or admit something, which lacks the proactive connotation of commitment that 'reaffirmed' carries.

Correct answer: exploit

Explanation: The verb 'exploit' fits grammatically and contextually as it means to make full use of and benefit from resources, which is appropriate in the context of utilizing sovereign space.

Meaning: 'Exploit' means to make use of a resource effectively, particularly in a beneficial way, which is relevant to the context of sovereignty and resource management.

Wrong options:

• harness: Harness means to control and make use of something, but it does not convey the same assertive connotation as 'exploit.'
• leverage: Leverage implies using something to maximum advantage, but it is less direct than 'exploit' in this context.
• capitalize: Capitalize means to take advantage of something, but it lacks the directness and assertiveness of 'exploit' in terms of resource utilization.

Correct answer: circumstances

Explanation: The noun 'circumstances' fits well as it refers to the conditions or facts affecting a situation, which is appropriate in the context of not threatening or using force.

Meaning: 'Circumstances' refers to the specific conditions or facts surrounding a situation, which is relevant to the context of international relations and agreements.

Wrong options:

• context: Context refers to the situation or background, but it does not fit as a condition under which actions are taken.
• position: Position implies a stance or location, which does not convey the idea of conditions affecting actions as 'circumstances' does.
• conditions: Conditions could fit, but 'circumstances' is more commonly used in this context to refer to the broader situation.