Nose
Spine
Mouth
Feet
Toothpick
Porcupine
Pentamerous
Dome
On the beach
Intertidal area only
Subtidal area only
Both intertidal area and subtidal areas
Purpuratus
Strongylocentrotus
Echinoderms
Animalia
Because sea urchins have large numbers of relatively big eggs
Because the eggs make great omlettes
Because a sea urchin's egg is relatively big
Because sea urchins have large numbers of eggs
Small fish
Sea cucumbers
Algae
Other sea urchins