Pasteur used swan-neck flasks in his experiments to test the validity of spontaneous generation. Suppose that after allowing the flasks to sit for a day, he had tilted one of these flasks so that the sterile broth entered the swan neck. Suppose he had then tilted the flask back to allow the broth to settle back into the round bowl of the flask before leaving it to sit undisturbed for another few days. What would have happened, and how would these results have affected conclusions about spontaneous generation?

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Explanation:

If Pasteur had tilted one of the flasks so that sterile broth entered the swan neck and then tilted it back to allow the broth to settle back, that particular flask would have had microbes growing in it after being left undisturbed for a few days.

Allowing the sterile broth to get to the neck of the swan would lead to the contamination of the broth because the swan neck is not sterile. If this had happened, the observation of growth of microbes in one of the flasks would have given further credence to spontaneous generation.

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