The experiments of which of the following scientists dismissed spontaneous generation theory once and for all?

Louis Pasteur by careful experimentation demonstrated that life comes only from pre-existing life. He showed that in pre-sterilised flasks, life did not come from killed yeast while in another flask open to air, new living organisms arose from ‘killed yeast’. Spontaneous generation theory was dismissed once and for all.

In Pasteur's experiments, he used swan-necked flasks that allowed air to enter but prevented dust and microorganisms from coming into direct contact with the broth inside. He boiled the broth to kill any existing microorganisms and then observed that no new microorganisms appeared in the broth, even though it was exposed to air. This demonstrated that the growth of microorganisms did not occur spontaneously from non-living matter but required the presence of pre-existing microorganisms introduced through the air.

These experiments, conducted in the mid-19th century, were instrumental in refuting the centuries-old belief in spontaneous generation, which suggested that life could arise spontaneously from non-living matter. Pasteur's work provided compelling experimental evidence against this idea and paved the way for our modern understanding of the microbial world and the principle that life arises from pre-existing life.