Demonstrated that the disease anthrax is caused by a bacterium and devised postulates for establishing causative relationship between a microbe and a disease.

Robert Koch

Explanation:

Robert Koch injected extract from infected animals into healthy mice. This resulted in the development of anthrax in mice. He incubated a part of the spleen containing the anthrax bacillus in beef serum. This allowed the growth and production of endospores by the bacteria.

He isolated the bacilli and the spores and injected into healthy mice. This caused the development of anthrax mice, He concluded that anthrax is caused by a bacterium. He correlated different types of microorganisms with a particular disease and developed Koch’s postulates.

According to these postulates,  all the diseased living beings should have the respective causative microorganism. The same must not be present in healthy organisms. isolation of causative microbes must be followed by the development of their pure culture.

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.