B) Pasteur

- Louis Pasteur rejected the theory of spontaneous generation through his experiments in the mid-19th century.
- Spontaneous generation was a widely accepted theory at the time, which proposed that living organisms could arise from non-living matter under certain conditions.
- Pasteur conducted a series of experiments to test this theory and proved that it was incorrect.
- He designed a special flask, known as the swan-neck flask, which had a long neck that curved downward. This design allowed air to enter the flask but prevented dust and microorganisms from entering.
- Pasteur then boiled broth in the flask to sterilize it and observed that no microorganisms grew in the broth as long as the flask remained sealed.
- However, when the flask was tilted or the neck was broken, microorganisms from the outside air entered the flask and contaminated the broth, leading to the growth of new organisms.
- This experiment showed that the presence of pre-existing microorganisms was necessary for the growth of new organisms, and they did not arise spontaneously from non-living matter.
- Pasteur's experiments provided strong evidence against the theory of spontaneous generation and supported the idea of biogenesis, which states that living organisms can only arise from pre-existing living organisms.
- His work had a significant impact on the field of microbiology and laid the foundation for the development of sterilization techniques and the germ theory of disease.
- Pasteur's rejection of spontaneous generation and his discoveries in microbiology revolutionized our understanding of the origin and spread of diseases, leading to significant advancements in the field of medicine and public health.