Why are there twelve constellations?

It comes from the zodiac in astronomy ~ ~ ~ ~

The earth revolves around the sun once a year. When the earth rotates, the sun can be seen from the earth. The sun moves slowly on the celestial sphere and among the stars, and the direction of movement is the same as that of the earth's revolution, that is, from west to east, it also moves in a big circle every year, which is called solar annual apparent movement. The path of the sun's annual apparent motion on the celestial sphere is the ecliptic. In other words: the earth's orbital plane expands infinitely, and the great circle intersecting the celestial sphere is the ecliptic.

The zodiac passes through 13 of 88 constellations except Ophiuchus. Starting from Pisces where the vernal equinox is located, they are Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn and Aquarius, which are collectively called the zodiac, also known as the zodiac.

Humans say that the constellation is just the position of the sun in the zodiac when someone is born, that is, a house ~