In terms of appearance, echinoderms are radially symmetrical, and the appearance of the sea urchin fits this characterization.
Echinoderms have a plumbing system in their bodies, and sea urchins also have one in their bodies.
Sea urchins live in the ocean and are marine animals, some with deep distributions and some with shallow distributions.
In terms of diet, sea urchins are omnivorous and can eat algae plants as well as animals such as hydroids and worms.
A, sea urchin is an animal sea urchin is a creature living in the ocean, their appearance looks more like plants, and basically do not move, so many people think they belong to plants.
In fact, not, sea urchins are actually animals.
In terms of classification, sea urchins belong to the animal kingdom, and all creatures in the animal kingdom belong to animals, as do sea urchins.
Animals are relative to plants, and organisms in the plant kingdom are plants.
The difference between sea urchins, as animals, and plants is relatively large.
In terms of movement, although sea urchins don't move in the water for a long time, they actually do move, just more slowly.
When sea urchins move, they rely on a number of tubular feet and spines on their bodies; plants, however, are largely immobile.
Also, on a microscopic level, the cells that make up a sea urchin are very different from those of a plant.
Sea urchins do not have a cell wall, but plant cells do.
Also, many plants have chloroplasts, which can be used for photosynthesis, but sea urchins do not.
Second, the sea urchin is what animals have been introduced above, the sea urchin is an animal.
And from the point of view of the specific classification, the sea urchin belongs to the phylum Echinodermata, which is a kind of echinoderms.
The sea urchin, as an echinoderm, also conforms to the basic characteristics of echinoderms.
For example, in terms of appearance, echinoderms are basically radially symmetrical, and sea urchins fit this characteristic.
Furthermore, for example, echinoderms generally have a plumbing system in their bodies, and sea urchins have that in their bodies as well.
Additionally, sea urchins can be categorized as marine animals if they are classified by their habitat, as they basically live in the ocean.
Specifically, sea urchins have a wide distribution range and are found all over the world.
Some sea urchins are found in relatively shallow areas, while others live at depths of several thousand meters, providing diversity.
From the point of view of food, sea urchins are omnivores, they can eat algae plants in the water, but also eat hydroids, worms and other animals.