Meaning: 'Gentle' means soft or mild, referring to a light breeze that is not strong or harsh.

Wrong options:

• Great: 'Great' implies something large or significant, which does not accurately describe the wind's intensity in this context.
• Safe: 'Safe' refers to the absence of danger, which is unrelated to the description of wind intensity.
• Arranged: 'Arranged' suggests organization or order, which does not apply to the natural movement of wind.

Correct answer: hot

Explanation: The word 'hot' is contextually appropriate as it describes the temperature of the spots where the air is warmed, fitting grammatically as it aligns with the description of the air rising due to being lighter than the surrounding air.

Meaning: 'Hot' refers to a high temperature, indicating areas that have been heated more than others.

Wrong options:

• cold: 'Cold' contradicts the context since it would not lead to the air rising; instead, it would sink.
• soft: 'Soft' describes texture rather than temperature, making it irrelevant in this context.
• humid: 'Humid' refers to moisture content in the air, which does not directly relate to the temperature needed for the air to rise.

Correct answer: heavier

Explanation: The word 'heavier' is grammatically correct as it describes the comparative weight of cool air, fitting logically into the context of why it sinks compared to the lighter, warmer air above.

Meaning: 'Heavier' means having more weight, indicating that cool air is denser than warm air, causing it to sink.

Wrong options:

• lighter: 'Lighter' would imply that cool air rises, which contradicts the explanation of air movement in the passage.
• colder: 'Colder' describes temperature but does not address the weight aspect necessary for the air to sink.
• warmer: 'Warmer' suggests a higher temperature, which is not applicable to the cool air that is sinking.

Correct answer: difference

Explanation: The word 'difference' fits grammatically and contextually as it refers to the variation in air temperature and pressure that causes winds to blow, aligning with the overall explanation of wind movement.

Meaning: 'Difference' refers to a distinction or variation, in this case, between high and low pressure areas that drive wind flow.

Wrong options:

• measure: 'Measure' refers to quantifying something, which does not apply to the concept of air movement.
• shortage: 'Shortage' implies a lack of something, which does not relate to the conditions necessary for wind to occur.
• settlement: 'Settlement' refers to a community or agreement, which is irrelevant to the scientific explanation of wind.

Correct answer: entire

Explanation: The word 'entire' is appropriate as it describes the whole globe, fitting grammatically and contextually to indicate that the winds affect all parts of the Earth, not just a portion.

Meaning: 'Entire' means whole or complete, indicating that the winds circulate across the whole globe.

Wrong options:

• great: 'Great' implies size but does not convey the idea of completeness necessary in this context.
• small: 'Small' contradicts the idea of global circulation, as it suggests a limited area.
• shaped: 'Shaped' refers to form or structure, which does not apply to the concept of wind circulation over the globe.