Final answer:
Koch's postulates were experimental steps developed by Robert Koch to establish a causal link between a microorganism and a disease. They were used to identify the causative agents of diseases such as anthrax, tuberculosis, and cholera.
Step-by-step explanation:
Robert Koch developed a set of postulates, known as Koch's postulates, to determine whether a particular disease is caused by a specific pathogen. These postulates were a series of experimental steps that involved comparing cultures from healthy and diseased animals to establish a causal link between a microorganism and a disease. Koch's postulates were instrumental in definitively identifying the causative agents of diseases such as anthrax, tuberculosis, and cholera.