The earthworm's vessel acts as a pump to push blood throughout the body.
-ventral
-capillary
-dorsal

The earthworm's ventral vessel serves to pump blood through out the posterior portion of the earthworm's body and the dorsal vessel supplies blood to the anterior portion of the body. Because the larger part is covered by the ventral vessels, it is the answer here.

This is what i found on google “phytoplankton, tiny organisms that live in the ocean, are autotrophs. some types of bacteria are autotrophs. most autotrophs use a process called photosynthesis to make their food.” i hope this you for what your looking for