Meaning: 'Caused' means to make something happen or to bring about an effect, indicating that the melting ice was responsible for the temperature drop.

Wrong options:

• featured: 'Featured' means to have something as a prominent part, which does not convey the idea of causing a temperature drop.
• denied: 'Denied' means to refuse or reject, which does not fit the context of explaining a consequence of melting ice.
• reflected: 'Reflected' implies showing or demonstrating something, which does not accurately describe the action of the melting ice affecting temperature.

Correct answer: Even though

Explanation: The phrase 'Even though' introduces a contrast, which is necessary here as it highlights the difference between the warming of the rest of the planet and the cooling in the North Atlantic. This fits both grammatically and contextually.

Meaning: 'Even though' is used to introduce a statement that contrasts with another, indicating that despite the warming elsewhere, the North Atlantic remained cold.

Wrong options:

• contrasting to: 'Contrasting to' is not a standard phrase in English and does not fit grammatically in this context.
• As if: 'As if' suggests a hypothetical situation, which does not align with the factual contrast being made in the sentence.
• Now that: 'Now that' implies a change in circumstances, which does not accurately reflect the ongoing situation described.

Correct answer: up

Explanation: The word 'up' is the correct preposition here, indicating an increase in temperature. It fits grammatically and contextually, as it describes the warming trend of the planet.

Meaning: 'Up' in this context means to increase or rise, referring to the temperature going higher.

Wrong options:

• in: 'In' does not convey the idea of an increase and would not fit the context of temperature change.
• off: 'Off' implies separation or removal, which does not relate to temperature changes.
• back: 'Back' suggests a return to a previous state, which does not accurately describe the ongoing warming trend.

Correct answer: around

Explanation: The word 'around' is appropriate here as it indicates a general time frame, fitting grammatically and contextually with the historical reference to 8000 years ago.

Meaning: 'Around' means approximately or in the vicinity of, used here to indicate a time period.

Wrong options:

• on: 'On' is used for specific dates or days, which does not fit the general time reference needed here.
• before: 'Before' indicates a prior time without the necessary context of a specific period, which does not match the sentence's structure.
• after: 'After' implies a subsequent time, which contradicts the historical context of the cooling event.

Correct answer: could

Explanation: The word 'could' is the correct modal verb here, indicating possibility. It fits grammatically and contextually, suggesting that a cooling event is a potential occurrence.

Meaning: 'Could' expresses a possibility or capability, indicating that cooling might happen again.

Wrong options:

• can: While 'can' indicates ability, it does not convey the same sense of possibility in a hypothetical context as 'could' does.
• should: 'Should' implies obligation or expectation, which does not fit the context of discussing potential future events.
• could have: 'Could have' suggests a past possibility that did not occur, which does not align with the current discussion of potential future events.