.
Which sequence is most correct?
galaxies began to form; stars were born in galaxies; planetary systems (like the solar system) formed around some stars; dust and gases in space drawn together by gravity
dust and gases in space drawn together by gravity; planetary systems (like the solar system) formed from dust and gases around some stars; galaxies began to form; stars were born in galaxies
dust and gases in space drawn together by gravity; galaxies began to form; stars were born in galaxies; planetary systems (like the solar system) formed around some stars
dust and gases in space drawn together by gravity; stars were born in galaxies; galaxies grew from dust and gas clouds; planetary systems (like the solar system) formed around some stars

(its actually not chemistry its science)