Why are celestial bodies in the solar system always located in the zodiac 12 constellation when viewed from the earth?

First of all, because the ecliptic 12 is made up of

The earth moves around the sun.

about

Zodiac plane

The swept stars.

but

Planets in the solar system

It basically revolves around the sun on a plane similar to the ecliptic plane of the earth.

So the planet you see, the sun, is fixed at 12. . . This is considered to be stipulated. .