If a piece of glassware were to become damaged during a lab the best thing to do would be to a. label it "damaged". b. let the teacher know about it. c. set it aside and get another one. d. throw it away and get another one.

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.