Which scientist read Pasteur's work and decided to investigate whether diseases were linked to specific germs?

• A. Koch
• B. van Leuwenhoek
• C. Lister
• D. Ulster

Answer: (A)

The idea being tested is how scientists moved from seeing germs to proving that specific diseases are caused by specific microbes. After Pasteur proposed that microbes could cause disease, Robert Koch took up the challenge of proving that link with solid evidence. He focused on anthrax, showing that a particular germ, Bacillus anthracis, was present in diseased animals and could produce disease when transferred to healthy animals. He also developed a rigorous method—what we call Koch’s postulates—for proving that a microbe causes a disease. This gave concrete proof that each disease could be tied to a specific germ, turning germ theory into a practical, testable rule. The other figures fit different roles in medical history (observation of microbes earlier, antiseptic advances, or unrelated names), but Koch is the one who read Pasteur’s ideas and directly pursued the germ-disease link.