Final answer:
The seasonal variation in daylength decreases with increasing distance from the equator because the Earth's axis tilts less at higher latitudes.
Step-by-step explanation:
The correct answer is D) Decreases, the Earth's axis tilts less at higher latitudes.
The seasonal variation in daylength decreases with increasing distance from the equator because the Earth's axis tilts less at higher latitudes.
When the Earth's axis tilts less, the angle at which the Sun's rays strike the Earth's surface decreases, resulting in less variation in daylength and less direct sunlight.