Final answer:
On June 21, the North Pole experiences the most daylight hours with continuous sunlight, while the South Pole has the fewest with complete darkness. The correct answer is Most: North Pole, Fewest: South Pole.
Step-by-step explanation:
The locations that experience the most and fewest daylight hours on June 21 are the North Pole and the South Pole, respectively. On this date, which is the summer solstice in the Northern Hemisphere, the North Pole receives 24 hours of continuous daylight. Conversely, the South Pole is veiled in 24 hours of darkness. Therefore, the correct answer to the question which locations experienced the most and fewest daylight hours on June 21 would be Most: North Pole, Fewest: South Pole. The Tropic of Cancer, on this day, is the place where the Sun is at its zenith at noon, but it does not have the most daylight hours compared to the North Pole.
If the tilt of Earth's axis were only 5°, the Tropic of Cancer and the Arctic Circle would be at latitudes closer to the equator, with the Tropic of Cancer at 5° N and the Arctic Circle at 85° N. This change in the Earth's tilt would result in less extreme seasons and a smaller variation in day lengths throughout the year.