Does b complex vitamin have all the other b vitamins in it? what makes it complex?

Yes; having all : By definition, b complex contains all of the b vitamins. In this case "complex" means "made up of inter-related parts" like the military-industrial complex. Out bodies need to convert some b's to the active form, like b6 to pyridoxal-5-phosphate and Folic Acid to 5-mthf. The best quality b complexes contain some of the "activated" forms as some people don't readily make the conversions!