the earthworm

EARTHWORM:

Kingdom Animalia
Phylum Annelida
Class Oligochaeta

The earthworm is the best-known member of the phylum Annelida, the segmented worms. Annelids are bilaterally symmetrical, and their bodies are divided into segments both externally and internally. They have a tube-within-a-tube body structure. The outer tube is the body wall, while the inner tube is the digestive tract. The cavity between the outer and inner tubes is the coelom.



CIRCULATORY SYSTEM
As food is digested, the blood in the circulatory system picks it up for distribution to all the cells of the body. In simpler...