Which concept is most directly supported by Pasteur's work on fermentation?

• A. Germ theory of disease
• B. Spontaneous generation
• C. Abiogenesis
• D. Miasma theory

Answer: (A)

The key idea here is that microorganisms are the agents responsible for biological changes, including disease. Pasteur’s work on fermentation showed that specific living microbes drive fermentation: yeasts carry out alcohol fermentation, while other microbes produce different products. Importantly, when he prevented microbial contamination, fermentation didn’t proceed, and when microbes were allowed in, it did. This demonstrated that invisible agents—microorganisms—are responsible for these processes, not some nonliving force or purely chemical reactions.

From this, the germ theory of disease follows: many diseases are caused by microorganisms. Pasteur’s fermentation results provided the clearest, direct demonstration that microbes can cause real biological effects, paving the way for understanding disease causation by pathogens. The other ideas—spontaneous generation and abiogenesis, which claim life arises spontaneously from nonliving matter, and miasma theory, which attributes disease to bad air—do not fit as directly supported by this fermentation evidence, since the core takeaway is microbial causation rather than origins or airborne miasmas.