Chapter 25, Problem 7A

Summary Introduction

Introduction :

The Planaria is an invertebrate. The planaria consist of flatworms.

Answer to Problem 7A

Correct answer :

Option (D).

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) flame cells. The flame cells are the cells of excretory system in the flatworms. The flame cells are not involved in the movement of the planaria, it is only involved in the excretion of the waste. Hence, the correct answer is option (D).

Explanation for incorrect answer :

Option (A)Cilia. The cilia are fine hair like structure that helps in movement. Hence, it is an incorrect answer.

Option (B) muscles. The muscles are responsible for the contraction that cause movement of the organism. Hence, it is an incorrect answer.

Option (C) mucus. The mucus provides the slippery environment that help in swift movement. Hence, it is an incorrect answer.