Final answer:
The Arctic Circle is the southernmost latitude in the Northern Hemisphere where the sun is visible for 24 hours during the summer solstice, known as the 'land of the midnight Sun'. Adjustments in Earth's axial tilt would alter the Arctic Circle's position, affecting seasonal variations and daylight hours.
Step-by-step explanation:
Regions north of the Arctic Circle are termed the "land of the midnight Sun" due to an astronomical phenomenon where, during the summer solstice, the sun is visible for a full 24 hours. This occurs because the tilt of the Earth's axis allows the sun to remain above the horizon throughout the day and night at these high latitudes.
The Arctic Circle is set at 66.5° north of the equator, marking the southernmost point of this 24-hour sunlight occurrence on the June solstice. In contrast, during the winter solstice, the same regions experience a polar night where the sun does not rise above the horizon for 24 hours.
Changes in the Earth's axial tilt would affect the positioning of the Arctic Circle and the Tropic of Cancer, resulting in milder seasons and less variation in the sun's path if the tilt were reduced to 16°, positioning the Arctic Circle at 74° and the Tropic of Cancer at 16° N latitude, with a latitude difference of 58° between them.