Which conclusion did John Needham draw after considering Francesco Redi's experiments on spontaneous generation?

• A. All living things arise only from pre-existing life, disproving spontaneous generation.
• B. Air is not necessary for the generation of life in nutrient broths.
• C. Microorganisms cannot survive boiling and therefore do not appear in broths.
• D. Boiled broths could still give rise to life, supporting spontaneous generation.

Answer: (D)

Verified step by step guidance

1. Review Francesco Redi's experiment, which involved placing meat in jars—some covered and some uncovered—to test if maggots would spontaneously generate. Redi concluded that maggots only appeared in uncovered jars where flies could lay eggs, suggesting that life does not arise spontaneously from nonliving matter.
2. Understand that John Needham conducted experiments with nutrient broths, boiling them to kill existing microorganisms and then sealing the flasks. Despite boiling, microbial growth still appeared in the broths after some time.
3. Analyze Needham's interpretation: since the broths were boiled (which should kill all life) and yet life appeared, he concluded that life could spontaneously arise from nonliving matter in the nutrient broth.
4. Contrast Needham's conclusion with Redi's findings: while Redi disproved spontaneous generation for larger organisms like maggots, Needham believed that microorganisms could still arise spontaneously under certain conditions.
5. Summarize that Needham's conclusion was that boiled broths could still give rise to life, which he took as support for the theory of spontaneous generation, despite Redi's earlier evidence against it.