Which component of the gastrointestinal system can synthesize certain vitamins? circular folds liver enzymes gi flora intestinal yeasts?

The intestinal flora are the components of the gastrointestinal system that can synthesize certain vitamins. 
Intestinal bacteria synthesizes vitamins such as biotin, vitamin B12, folic acid and thiamine. In addition it also performs other functions such as fermenting indigestible carbohydrates to short chain fatty acids such as propionate, butyrate and acetate. 

Ifound this on google “aristotle (384–322 bc) in western scientific taxonomy the greek philosopher aristotle was the first to classify all living things, and some of his groups are still used today, like the vertebrates and invertebrates, which he called animals with blood and without blood.” i hope this you for what your looking for.

This type of galaxy is an approximately ellipsoidal shape and a smooth, nearly featureless image. they are the largest single star systems, in the universe and are built by the collisions of many smaller galaxies.