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