Answer:
Robert Koch and Louis Pasteur.
Step-by-step explanation:
Robert Koch and Louis Pasteur are the two scientists' who discover the presence of microorganisms and their relationship to diseases. In 1876, Robert Koch performed experiments and made a hypothesis that microbes can cause disease in humans and other organisms while on the other hand, Louis Pasteur performed many experiments between the years 1860 and 1864 and made a hypothesis that the puerperal fever happens due to the infection of pyogenic vibrio in the blood.