A.I. Explanation:

Correct answer: plan

Explanation: The word 'plan' fits grammatically as it is a verb that indicates the action of creating a strategy, which aligns with the context of conservationists meeting to organize a campaign. It is the most appropriate choice as it conveys the intent to devise a structured approach.

Meaning: 'Plan' means to create a detailed proposal for achieving something, in this case, a campaign.

Wrong options:

• design: While 'design' can imply creating a plan, it is more focused on the aesthetic or structural aspect rather than the strategic aspect needed here.
• programme: This term typically refers to a scheduled series of events or activities, which does not fit the context of strategizing a campaign.
• form: 'Form' suggests creating something physical or tangible, which does not align with the abstract nature of planning a campaign.

Correct answer: still

Explanation: The word 'still' indicates that rhino horn remains a part of traditional medicine, which is the intended meaning in this context. It fits grammatically as it suggests continuity, which is essential for understanding the ongoing issue.

Meaning: 'Still' means that something continues to be the case, indicating that rhino horn is currently used in traditional medicine.

Wrong options:

• hardly: This word implies a minimal amount or degree, which contradicts the context of rhino horn being a significant part of traditional medicine.
• even: 'Even' is used to emphasize something unexpected, but it does not convey the ongoing nature of the situation as effectively as 'still.'
• nearly: This term suggests proximity to a condition but does not accurately reflect the ongoing use of rhino horn in traditional medicine.

Correct answer: switch

Explanation: The word 'switch' implies a change from one thing to another, which is appropriate in the context of persuading countries to change their practices regarding rhino horn. It fits grammatically and contextually as it suggests a direct action of changing to substitutes.

Meaning: 'Switch' means to change from one thing to another, indicating a transition to alternative options.

Wrong options:

• vary: This term suggests differences or changes but does not imply a direct action of changing practices as 'switch' does.
• modify: While 'modify' implies making changes, it does not convey the decisive action of changing to substitutes as clearly as 'switch.'
• adjust: This word suggests making small changes, which does not capture the significant change implied by moving to substitutes.

Correct answer: threat

Explanation: The word 'threat' appropriately describes a danger or risk to the survival of the rhinoceros, fitting both grammatically and contextually. It conveys the seriousness of the situation regarding rhino conservation.

Meaning: 'Threat' refers to a potential cause of harm or danger, highlighting the risks faced by rhinoceroses.

Wrong options:

• danger: While 'danger' is similar, it lacks the nuance of a potential risk that 'threat' conveys in this context.
• disaster: This term refers to a catastrophic event, which does not accurately describe the ongoing risk to rhinos as 'threat' does.
• menace: Although 'menace' implies a looming danger, it is less commonly used in this context and does not fit as smoothly as 'threat.'

Correct answer: refusal

Explanation: The word 'refusal' indicates a rejection of action, which is appropriate in the context of countries not enforcing a ban. It fits grammatically and contextually, emphasizing the inaction that contributes to the problem.

Meaning: 'Refusal' means the act of saying no to something, in this case, the enforcement of a ban on rhino horn.

Wrong options:

• rejection: While similar, 'rejection' typically refers to dismissing something rather than the act of not taking action, which is more accurately captured by 'refusal.'
• denial: This term implies a refusal to accept something as true, which does not fit the context of enforcing a ban as well as 'refusal.'
• protest: This word suggests an expression of objection, which does not align with the context of countries not taking action.

Correct answer: trading

Explanation: The word 'trading' fits grammatically and contextually as it refers to the act of buying and selling, which is relevant to the context of rhino horn. It indicates the commercial activity that needs to be banned.

Meaning: 'Trading' means the action of buying and selling goods, in this case, rhino horn.

Wrong options:

• business: This term is too broad and does not specifically refer to the act of buying and selling rhino horn, making it less precise than 'trading.'
• commerce: While related, 'commerce' is a more formal term that does not convey the specific action of trading as effectively as 'trading.'
• selling: This word focuses only on the act of selling, omitting the buying aspect, which is essential in the context of trading.