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