NEET Biology Structural Organisation In Animals Based Practice Questions & Answers with Viewers Discussion and Detailed Explanation

Answer: (a)

In Pheretima, next to stomach is the intestine. It is a long, wide and thin walled tube extending from 15th segment to the last. Second or middle part of the intestine lies between $27^{th}$ segment up to 23–25 segments in front of anus. This is characterised by the presence of a highly glandular and vascular longitudinal ridge, arising as a median in-growth of the dorsal aspect of the intestinal cavity. This is called the typhlosole. The typhlosole greatly increases the effective absorption area of the digested food in the intestine.