Final answer:
Lazzaro Spallanzani was an Italian biologist who contributed significantly to the refutation of spontaneous generation, demonstrating through his experiments that life does not spontaneously arise from non-living matter.
Step-by-step explanation:
Lazzaro Spallanzani was an 18th-century Italian biologist and physiologist known for his research in various areas of the natural sciences, including animal reproduction and echolocation. However, one of his major contributions to biology was his experimental refutation of the theory of spontaneous generation. Spallanzani designed meticulous experiments which contradicted earlier work by John Needham. He demonstrated that sealed flasks of boiled broth remained clear and free of microorganisms, thus arguing against the idea that life could emerge spontaneously from non-living matter. The theory of spontaneous generation posited that living organisms could arise from inanimate objects, a belief held for many centuries. Through his experiments, Spallanzani strengthened the case that microorganisms entered from the air and were not a product of spontaneous generation. This work laid the groundwork for the germ theory of disease and built upon the findings of previous scientists like Francesco Redi. His studies were a critical step forward in understanding the origin of life and the requirements for microbial growth, setting the stage for the eventual work of Louis Pasteur.