Final answer:
The constellations of the zodiac are located along the ecliptic, which is the path the Sun appears to take across the celestial sphere over the course of a year.
Step-by-step explanation:
The constellations of the zodiac fall along the ecliptic. The ecliptic is the apparent path that the Sun follows over the course of a year against the background of the stars, and it extends across the celestial sphere. The zodiac constellations are special because they are located within an 18-degree-wide belt centered on the ecliptic, and were considered significant by ancient astrologers due to the paths of the Sun, Moon, and planets lying in this region of the sky.