Question

Pasteur succeeded in disproving the theory of spontaneous generation because

• A. The laboratory was clean.
• B. He pulled out the neck of flask into a tube.
• C. He was lucky.
• D. Yeast used in flask were dead.

Answer 1

Answer: (B)

He pulled out the neck of flask into a tube.

The swan neck flask experiment, Pasteur filled a flask with medium, heated it to kill all life and then drew out the neck of the flask into a long S shape. This prevented microorganisms in the air from easily entering the flask, yet allowed some air interchange. If the swan neck was broken, microbes readily entered the flask and grew. Pasteur succeeded in disproving the theory of spontaneous generation by this experiment.

Therefore, the correct answer is option B.