B. Bicarbonate
<em>The blood brings bicarbonate to the lungs, and then it is exhaled as carbon dioxide. The kidneys also help regulate bicarbonate... it is excreted and reabsorbed by the kidneys.</em>
<em>The body's main response is to get rid of more carbonic acid and hold on to as much bicarbonate base in the kidneys as it can.</em>
An isolated colony on a selective medium is not considered a pure culture because inhibited organisms might be masked by the colonies. This statement is true.
On the basis of their constitution or usage, culture media can be classified into various groups; these include defined, complex, selective, as well as enrichment medium.
A selective medium consists of dyes or noxious substances/chemicals which inhibit the growth of specific microorganisms but promote the growth of other microbes.
A pure culture is a laboratory culture which contains a single species of microorganism. It is free from other microorganisms.
Since selective media affects the growth of distinct organisms differently, therefore, an isolated colony formed in such type of medium is not considered a pure culture.
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Reptile answer option no 1