Question

question 5
the imaginary boundary between the earth and sky is called the ___________.
celestial equator
horizon
south celestial pole
zenith
north celestial pole

Explanation:

The horizon is the apparent line that separates the earth from the sky. The celestial equator is an imaginary extension of Earth's equator into space. The south and north celestial poles are the points in the sky directly above Earth's South and North poles. The zenith is the point directly overhead.

Answer:

B. horizon