Explain how the zodiacal constellations are different from the other constellations.

They lie on the Ecliptic (apparent path of the Sun around Earth)

Explanation:

There are total 88 constellations in the sky out of which only 12 are considered as zodiacal constellations or Sun signs. This is because these are the constellations which lie on the Ecliptic.

Ecliptic is the apparent path of Sun around the Earth.

In other words, it can be said that the Sun appears to reside in 12 constellations throughout the year as the Earth revolves around it.