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