Which molecular formula corresponds to this model of a chemical compound? (black = carbon; red = oxygen; white = hydrogen) A ball-and-stick model has two black balls bonded to each other at center, with single-bonded red balls bonded to white balls above left and below right, and double-bonded red balls above right and below left. C2(OH)4 C2H2O4 C2H4O2 C4H2O2

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.