Which of the following best describes a key difference between Francesco Redi's and Louis Pasteur's experiments on spontaneous generation?

• A. Redi boiled his samples to kill microorganisms, while Pasteur did not use heat in his experiment.
• B. Redi focused on bacteria, while Pasteur focused on the origin of maggots.
• C. Redi used meat in jars to test for maggot formation, while Pasteur used nutrient broth in flasks to test for microbial growth.
• D. Redi's experiment involved the use of swan-neck flasks, while Pasteur used sealed jars.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the historical context of spontaneous generation, which is the hypothesis that living organisms can arise from nonliving matter.
2. Step 2: Review Francesco Redi's experiment, where he used meat placed in jars—some covered with gauze and some left open—to test whether maggots would appear without flies having direct access to the meat.
3. Step 3: Review Louis Pasteur's experiment, where he used nutrient broth in swan-neck flasks that allowed air in but prevented microbial contamination, to test whether microorganisms would grow without exposure to existing microbes.
4. Step 4: Compare the experimental designs: Redi's experiment focused on visible organisms (maggots) and used meat in jars, while Pasteur's experiment focused on microscopic organisms (bacteria and fungi) and used nutrient broth in specially designed flasks.
5. Step 5: Identify the key difference: Redi tested for maggot formation on meat in jars, whereas Pasteur tested for microbial growth in nutrient broth using swan-neck flasks to exclude contaminants.