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