Answer the following question given this paragraph: 

Annelids are segmented worms such as earthworms and leeches. Annelids have a coelom, closed circulatory system, excretory system, and complete digestive system. They also have a brain. Earthworms are important deposit feeders that help form and enrich soil. Leeches are either predators or parasites. Parasitic leeches feed off the blood of vertebrate hosts.


Q: Parasitic leeches feed off of what?

 Choices:

- brain

- tissue

- tumor

- blood

A:
blood
