Chapter 25, Problem 4STP

Summary Introduction

Introduction :

The Cnidaria is a phylum of animal Kingdom that contains aquatic animals that are radially symmetrical and have tissue level organization. They have an internal cavity and a mouth. The life od Cnidarians exist in two forms, medusa and polyp.

Answer to Problem 4STP

Correct answer :

Option (A).

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) Their tentacles contain cnidocyte. The tentacles of the Cnidarians contains specialized cells that helps in capturing prey and this is known as Cnidocyte. Hence, the correct answer is option (A).

Explanation for incorrect answer :

Option (B)their tentacles contain fibroblast. The fibroblast is a connective tissues present mostly in the vertebrates. Hence, it is an incorrect answer.

Option (C) they mostly live in fresh water. The cnidarians are found in both fresh and marine environment, most of them are marine. Hence, it is an incorrect answer.

Option (D) they spend some time as sessile animals. Some of the Cnidarians are sessile and some of them are completely free-living. Hence, it is an incorrect answer.