The major significance of Koch's work was that microorganisms are present in a diseased animal; option B.
Koch's postulates of disease refers to the postulates by the German Physician of the 19th century, Robert Koch. The postulates describes and helps to identify whether a particular microorganism is the cause of a given disease.
Koch's postulates are given below as follows:
Therefore, Koch's postulates most significantly helped to prove that microorganisms are present in a diseased animal.
In conclusion, Koch's postulates were significant in explaining the role of microorganisms in disease conditions.
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