Spine
Mouth
Nose
Feet
Porcupine
Pentamerous
Dome
Toothpick
Strongylocentrotus
Echinoderms
Purpuratus
Animalia
Intertidal area only
On the beach
Subtidal area only
Both intertidal area and subtidal areas
Small fish
Other sea urchins
Sea cucumbers
Algae
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