because they have some specialities to which they can only survive in the water such as they begin their lives as free swimming bilaterally symmetrical larvae etc.for e.g:star fish,sand dollar,sea-cucumber etc.
Because they did not come to land. First one to come to land are amphibians but they are going to water for reproduction. Reptiles are the first form to fully adapt for terrestial environment.
Yes Eventually echinoderms do live in water.
echinoderms, cnidaria and other forms
Echinoderms usually feed on smaller creatures in the sea floor. They also provide food for other larger fish within the ocean.
There are a number of different reasons why an animal that lives on land may be unable to live in water. The main reason is that their bodies are not adapted to such an environment, rendering them unable to survive in those conditions.Other reasons may include:Being unable to hunt or consume water-dwelling creatures.Being unable to swim for long enough periods of time (if at all).Being unable to breath sustainably when swimming.
Echinoderms, like all animals, are heterotrophs and need to eat food to survive.
Echinoderms have all the same organs as are normally found concentrated in the head only they have them scattered. So what if their eyes are on their legs if they still see. It is the seeing that is important, not the location of the eyes.
Plants survive in land by the water
It can survive on land because it has lungs now.
It can survive on land because it has lungs now.
A. Arthropods
Echinoderms are in the Animalia kingdom.
The scientific name for Echinoderms is Echinodermata.