Answer :
Final answer:
Earth's rotational axis precesses every 26,000 years, separate from its daily rotation or annual revolution. Therefore, the correct answer to the question is c) 26,000 years.
Explanation:
The Earth's rotational axis experiences a slow, conical movement known as precession, which is similar to the wobble of a spinning top. This precessional movement completes one full cycle approximately every 26,000 years. This phenomenon is caused by the gravitational pull of the Sun and the Moon acting on Earth's equatorial bulge. Earth's daily rotation on its axis, which takes about 24 hours, contributes to the alternation of day and night, and its revolution around the Sun, taking approximately 365.24 days, defines our year. However, these are separate motions from the slow precession of the axis.
