question: silkworm:spinning:silkworm cocoon
choices.label: A B C D
choices.text: worm:infection:cordyceps trees:processing:paper soybean:fermentation:bean paste coal:burning:electricity
explanation: "silkworm cocoons" are formed by "silkworms" through "spinning", "silkworms" are animals, "spinning" is the natural behavior of "silkworms", and "silkworm cocoons" are products. "cordyceps" is formed by "worms" through "infection", "worms" are animals, "infection" is the natural behavior of "worms", and "cordyceps" is a product. "Tree" is "processed" to form "paper", but this process requires human intervention. "Soybean" is "fermented" to form "bean paste", but this process requires human intervention. "Coal" is "burned" to form "electricity", but this process requires human intervention.