The term fastidiousness refers to the complexity of an organism's nutritional requirements. A fastidious microorganism will only grow if the culture medium provides the necessary nutrients. This table provides the readings on the optical density from bacterial cultures. This reading gives an indication of the concentration of the bacteria in the culture; the higher the concentration of bacteria, the greater scatter of light and the higher value of optical density. Yeast extract broth, nutrient broth and glucose broth are culture media which are enriched with more nutrients. In all these three media, S.mitis had the lowest optical density, meaning the lowest concentration. We can conclude that S.mitis is the most fastidious microorganism of the three. Then comes A.faecalis and the least fastidious of the three is E.coli.