Question

Which phylum is characterized by animals that have a segmented body?

(A) Cnidaria

(B) Platyhelminthes

(C) Arthropoda

(D) Mollusca

Short answer

(A) The option“Cnidaria” is false.

(B) The option “Platyhelminthes” is false.

(C) The option “Arthropoda” is true.

(D) The option “Mollusca” is false.

Step-by-step solution

Animal kingdom

The eukaryotic domain of life comprises four distinct kingdoms, namely, Animalia, Protista, Plantae, and Fungi. The Kingdom Animalia contains heterotrophic organisms with multicellular bodies; these organisms mostly have the ability to locomote.

Animals are found in terrestrial as well as aquatic environments.

Explanation of option ‘(A)’

Cnidaria is one of the phyla of the invertebrate group. It is characterized by the presence of stinging cnidoblast cells, a soft body with a central gastrovascular cavity, and radial symmetry.

Thus, the body of Cindarians is not characterized by the presence of segmentation.

Therefore, the given option is false.

Explanation of option ‘(B)’

The members of the phylum Platyhelminthes are characterized by the presence of a soft, dorsoventrally flattened body that exhibits bilateral symmetry. There is no segmentation, and the body also lacks cavities.

Thus, Platyhelminthes does not contain a segmented body.

Therefore, the given option is false.

Explanation of option ‘(C)’

Arthropoda is the animal phylum with the highest species diversity, and the majority of animals present in the world belong to this group. It is characterized by a segmented body that remains protected within an exoskeleton and comprises jointed appendages.

Thus, this phylum is characterized by segmentation.

Therefore, the given option is true.

Explanation of option ‘(D)’

In the phylum Mollusca, the organisms have a soft body that remains covered with a mantle, and there is no segmentation. The internal soft body has three parts, foot, visceral mass, and head.

Thus, segmentation is not found in the body of mollusc organisms.

Therefore, the given option is false.