Which structure is lacking in members of phylum echinodermata?

Members of the phylum Echinodermata lack the following body system:

Excretory organ, Brain, And also no respiratory pigment in their blood

Most of the common marine invertebrates that you see in the aquarium or on the beach all belong to the phylum called Echinodermata.

Further Explanation

Some of the examples of these marine invertebrates animals include sea urchins, starfish, sand dollars, basket stars, brittle stars and many more.

Echinodermata is a word that is derived from the Greek word “spiny fish” and this word best describes these animals because most of them are covered with bumps, for example, sand dollars and sea cucumbers are covered with one form of bumps or another.

However, Echinodermata bodily system lacks the following:

They do not possess a specialized excretory systemThey lack brainTheir blood does not contain respiratory systemThey also lack excretory organ and diffuses wastes out into the outside environment through their respiratory surfaces.

These invertebrate animals are marine species: they live only in salt water and there are none of their classes that reside on the land.

They are found almost at every ocean and the largest of animals that do not reside either on land or freshwater.

Most of these animals can reproduce sexually and can also restore or regenerate some of their lost body part such as the limbs and tissue.

LEARN MORE:

Which characteristics of the skeleton of members of phylum echinodermata is unique compared to the typical skeletons of members of clade protostomia Phylum echinodermata  

KEYWORDS:

phylum echinodermatafresh watermarine habitatstarfishsand dollars

Icant be totally sure but i would say with confidence that it is example #1 about cells.

They use the si unit, or metric system its all the same thing