Robert Koch is best known for which of the following contributions?

1. discovery of Archaea

2. discovery of Bacteria

3. identifying distinctions between Bacteria and Archaea

4. establishing a link between bacteria and disease

Robert Koch is best known for establishing a link between bacteria and disease.

Robert Koch was a German doctor that made an important contribution to the field of microbiology and public health. During his experiments he identified the particular microorganisms that cause diseases such as tuberculosis, cholera, and anthrax. Koch's research resulted to the development of Koch's postulates, which are four general principles that links specific microorganisms (such as bacteria) to specific diseases and is being used today in medical microbiology as a standard.