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