Meaning: 'Action' refers to the process of doing something, especially to achieve an aim, which in this context relates to the UN's ability to address various global issues.

Wrong options:

• reaction: 'Reaction' implies a response to something that has already happened, which does not fit the proactive context of the UN's capabilities.
• expectation: 'Expectation' refers to a belief about what will happen in the future, which does not align with the UN's active role in taking measures.
• expression: 'Expression' relates to conveying thoughts or feelings, which does not fit the context of taking measures or steps.

Correct answer: express

Explanation: The verb 'express' is appropriate here as it indicates the action of conveying views, fitting grammatically with the subject 'Member States' and contextually with the idea of sharing opinions in a forum.

Meaning: 'Express' means to convey or communicate thoughts, feelings, or opinions, which is what the Member States do in the UN's forums.

Wrong options:

• regret: 'Regret' implies a feeling of sadness or disappointment about something that has happened, which does not fit the context of sharing views.
• extend: 'Extend' generally means to increase in length or duration, which does not apply to the act of conveying views.
• press: 'Press' can mean to apply pressure or insist, which does not align with the context of simply sharing opinions.

Correct answer: corner

Explanation: The word 'corner' fits well as it refers to a specific area or part of something, and in this context, it conveys the idea of reaching every part of the globe, making it a suitable choice grammatically and contextually.

Meaning: 'Corner' in this context means a part or region of the world, emphasizing the global reach of the UN's work.

Wrong options:

• place: 'Place' is too vague and does not convey the same sense of specificity as 'corner' in relation to the globe.
• time: 'Time' refers to a period or duration, which does not fit the spatial context of the sentence.
• stage: 'Stage' typically refers to a particular point in a process or development, which does not align with the geographical context.

Correct answer: prevention

Explanation: The noun 'prevention' fits grammatically as it complements the context of the UN's efforts to stop conflicts before they escalate, making it the most logical choice in this context.

Meaning: 'Prevention' refers to the act of stopping something from happening, particularly in the context of avoiding conflicts.

Wrong options:

• aggregation: 'Aggregation' refers to the process of collecting or gathering, which does not fit the context of stopping conflicts.
• implementation: 'Implementation' means putting something into effect, which does not align with the proactive nature of preventing conflicts.
• extension: 'Extension' implies lengthening or expanding, which does not relate to the concept of stopping or preventing conflicts.