Question

Regarding blood circulation, it maybe said that in Pheretima the dorsal vessel is a

• A. Collecting vessel in first two segments and distributing vessel in other
• B. Distributing vessel in the first five segments and collecting vessel in other
• C. Collecting vessel in thirteen, segments and distributing vessel in intestinal
• D. Distributing vessel in first thirteen segments and collecting vessel in intestinal region

Answer 1

The correct option is D Distributing vessel in first thirteen segments and collecting vessel in intestinal region

Dorsal blood vessel of earthworm is the largest blood vessel. It occurs mid dorsally above the alimentary canal and runs from one end of the body to other. It collects blood from various parts behind the 13${}^{th}$ segment, however in the first thirteen segments, it behaves a distributing channel.