Which scientists demonstrated that spontaneous generation was incorrect?

• A. Louis Pasteur
• B. Francisco Redi and Louis Pasteur
• C. Alexander Fleming
• D. Charles Darwin

Answer: (B)

The fundamental idea being tested is whether life can arise from nonliving matter. Francesco Redi challenged this with a simple, well-controlled setup: meat in jars that were kept sealed, left open to the air, or covered with gauze. Only the jars open to the environment produced maggots, while the sealed ones did not, showing that the offspring came from eggs laid by flies, not spontaneously from the meat.

Louis Pasteur extended the investigation with a broth in swan-neck flasks. The curved neck allowed air to reach the broth but trapped dust and microbes, so no microorganisms appeared in the broth unless the flask was tipped or broke. This demonstrated that microorganisms come from preexisting life in the environment, not from inanimate matter spontaneously generating.

Other scientists listed didn’t perform the key experiments addressing spontaneous generation—Alexander Fleming discovered antibiotics, and Charles Darwin proposed natural selection. The combined evidence from Redi and Pasteur specifically shows that life does not spontaneously arise from nonliving material.