What purpose do cooling towers serve in a nuclear power plant?

A. to retain the nuclear gases emitted from the nuclear reactions
B. to provide a location for the heated water to cool and condense
C. to maintain the high temperatures required for the nuclear reactions
D. to act as a barrier to contain radiation in case of a possible meltdown

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.