蚯蚓切成两段，能活几条？

Cut an earthworm, and it does not become two worms. 把蚯蚓切成两段，不会变成两条蚯蚓。 Only the part with the thick band can survive. 只有带环带的那头，才能活。 That part grows a new tail. 那头，能长出一条新尾巴。 The other head-less part usually dies. 没有环带的那头，多半活不成。 So it is one worm that stays alive, not two. 所以活下来的，是一条而不是两条。 Earthworms do help soil stay healthy. 不过蚯蚓，确实能让泥土更健康。