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