What phenomenon causes the day-night cycle?

• A. Rotation
• B. Orbit
• C. Eclipse
• D. Moon phases

Answer: (A)

Day and night come from Earth spinning on its axis. As the planet rotates, different parts of the surface turn toward or away from the Sun. When your location faces the Sun, you experience daytime; when it faces away, it’s nighttime. This rotation happens roughly once every 24 hours, giving the daily cycle. The tilt of Earth’s axis changes how long daylight lasts at different times of year, especially at higher latitudes, but the basic cause of the day-night pattern is the planet’s rotation. The other ideas refer to different motions or events: orbit is the yearly path around the Sun that drives seasons, a solar eclipse is a rare alignment that briefly blocks sunlight, and Moon phases come from the Moon’s motion around Earth and how much of its sunlit side we see.