Question

how did francesco redi disprove the idea of spontaneous generation?
he showed that flies were not produced by meat.
he showed that microorganisms are present in air.
he showed that microorganisms cause disease.
he showed that flies spread disease.

Explanation:

Francesco Redi's experiment involved placing meat in jars, some covered and some uncovered. Uncovered jars had flies and maggots, covered ones (preventing fly access) didn't have maggots on the meat, showing flies weren't produced by meat, disproving spontaneous generation. Other options: showing microbes in air was Pasteur - like, microbes causing disease is germ theory (Koch/Pasteur), and flies spreading disease is about disease transmission, not spontaneous generation.

Answer:

A. He showed that flies were not produced by meat.