for protection
No, a sea urchin and a sea anemone are two different sea creatures nothingalike.They do have some alike characteristics.like they both use their long tentacles , or spikes for protection.
Sea Urchin !
the sea urchin has many adaptions like its spikes to protect it self from predators.
they use the poison in there spines to defend themselvesfor example when a predittor gets to close or steps on the sea urchin it releases a poision.
they puff up like a ball with spikes. It looks something like sea urchin when it puffs up.
The classification of a Sea Urchin is Echinoidea
sea urchin
A sea urchin does move, but not very frequently.
because the crab needs the sea urchin for protection and the sea urchin needs the crab for food
Ummm...it's the thing from which a sea urchin hatches?
Depending on the species, sea urchins range in size from a few inches across (small rock-boring urchins) to a foot or more across (pencil urchins and venomous hollow-spined urchins). THATS NOT HELPFUL!!
We eat it raw; it is a delicacy for us.