Which one of these statements is correct about the behavior of an observer's zenith (the vertical direction directly overhead) over a period of 1 year if the observer were standing on Earth's equator?
A) The angle between the zenith and Earth's spin axis will vary between +23.5° and -23.5° over this period.
B) The zenith will always be perpendicular to Earth's spin axis.
C) The zenith will always remain at a fixed angle of 23.5° to the spin axis of Earth.
D) The zenith will always be parallel to Earth's spin axis.

Question

Quizplus · Accepted Answer

The zenith is always perpendicular to the Earth's surface at the observer's location, and since the equator is perpendicular to the Earth's spin axis, the zenith will always be perpendicular to the spin axis at the equator.

Which One of These Statements Is Correct About the Behavior