Question

The only phylum in the group Parazoans is ________. A. Porifera B. Cnidaria C. Lophotrochozoa D. Ctenophora E. Ecdysozoa

Answer 1

Answer:

A. Porifera

Explanation:

Parazoan is a sub-kingdom of animal consisting only of the phylum of sponges (porifera), having two tissue layers only and lacking a nervous system and true digestive cavity.

They have certain characteristics like: sponges are marine, but there are some freshwater sponges that enjoy their water without salt. Most sponges do not have any type of symmetry, but some are radially symmetrical and they come in a variety of shapes, colors, and sizes, they are multicellular, heterotrophic and lack cell walls. Unlike other organisms, sponges lack true tissues and organs.

The mesohyl functions as an endoskeleton in most sponges, and is the only skeleton in soft sponges. This mesohyl is stiffened by mineral spicules, by spongin fibers or both.