What term describes the spinning of an object around its own axis, such as the Earth completing a rotation?

• A. Ocean Basin
• B. Revolution
• C. Venus
• D. Rotation

Answer: (D)

Rotation is the term describing the spinning of an object around its own axis. An axis is an imaginary line that runs through the center of the object, and when it spins around that line, that motion is rotation. For Earth, this rotation on its axis takes about 24 hours and creates day and night as different parts of the planet face toward or away from the Sun. This is different from revolution, which is motion around another body—Earth’s revolution is its orbit around the Sun, taking about a year. The other options don’t describe spinning in place: an Ocean Basin is a geographic feature, Venus is a planet, and revolution refers to orbital motion, not spinning on an axis.