Most vitamins can be obtained from a variety of sources, both animal and plant based; vitamin _____, however, is not produced by plants at all and can only be found in milk, eggs, or meat. (Bacteria are the source used when vitamin pills are made.)

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.