Question

Listed following are the latitudes of several locations on Earth. Rank these latitudes from left to right based on the maximum altitude (on the meridian) at which you would see a star with a declination of 0°, from lowest altitude (nearest the horizon) to highest altitude (farthest above the horizon).
The diagrams show a person standing on the Earth's surface looking up at the sky in the direction or altitude indicated.

Answer 1

A declination of 0 degrees means the star is on the celestial equator. The star therefore follows the path of the celestial equator across the local sky, which means it rises due east, crosses the meridian at an altitude of 90 degrees minus your latitude, and sets due west.

This means the answer would be:

Nearest the Horizon
latitude 70 degrees N
latitude 50 degrees N
latitude 40 degrees N
latitude 30 degrees N
latitude 10 degrees N
Farthest Above the Horizon