Chapter 25, Problem 15A

Summary Introduction

Introduction :

The round worms are called so because their body is cylindrical and long. They are bilaterally symmetrical. The ends of the worms are tapered or pointy at both ends. They are intestinal parasites and they are not involved in active movements. So, their body lack segmentation.

Answer to Problem 15A

Correct answer :

Option (B).

Explanation of Solution

Explanation/justification for the correct answer :

Option (B) Gut. The picture illustrates the pseudocoelom, which gives rise to a separate gut in the round worm. Hence, the correct answer is option (A).

Explanation for incorrect answer :

Option (A) Coelom. The roundworm lacks true coelom. Hence, it is an incorrect answer.

Option (C) mantle. The mantle is a characteristics of mollusks. Hence, it is an incorrect answer.

Option (D) segments. The round worm areunsegemented. Hence, it is an incorrect answer.