Final answer:
The dorsal blood vessel transports the blood toward the posterior end of the worm.
Step-by-step explanation:
The dorsal blood vessel transports the blood toward the posterior of the end of the worm. In annelids, such as worms, the circulatory system consists of a closed network of blood vessels. The dorsal blood vessel runs along the top of the worm's body, while the ventral blood vessel runs along the belly. The dorsal blood vessel carries blood towards the posterior end of the worm, while the ventral blood vessel carries blood towards the anterior end.