dorsal seta

例句：

1. 1. The animal has a dorsal seta on its back that can be used to communicate with other members of the species.
   这种动物背部有一根背刺，可以用来与其他物种的成员进行交流。
2. 2. The dorsal seta is a unique feature of this species and is used for defense against predators.
   背刺是这种物种的一个独特特征，用来抵御捕食者。
3. 3. The dorsal seta is not visible to the naked eye, but it plays an important role in the animal's behavior and communication.
   背刺肉眼不可见，但它在动物的行为和沟通中起着重要作用。